FIELD OF INVENTION
[0001] The present subject matter relates to device-to-device communication and,
5 more particularly but not exclusively, to channel resource allocation for device-to-device
communication.
BACKGROUND
[0002] In recent times there has been a rapid increase in the use of cellular
communication devices, resulting in a corresponding increase in the volume of network
10 traffic exchanged over the cellular communication network. Data transfer over the cellular
communication networks may thus not be a speedy and efficient process. Network operators
^ have been involved in development of alternate communication techniques, such as deviceto-
device (D2D) communication, to reduce the load on the cellular communication networks.
In D2D communication, a wireless communication link is established directly between two
15 communication devices. For example, WiFi Direct is a technique by which devices can
directly communicate over WiFi channels without any intermediary nodes.
[0003] Using D2D communication instead of the conventional wireless network may
resuh in various benefits. For instance, using a wireless communication link established
directly between two communication devices may result in reduction in transmitter power
20 consumption; improvement in network resource utilization; increased cellular network
capacity and coverage; support for additional services, such as heavy data packet transfer;
and peer-to-peer services, such as home entertainment systems and vehicle-to-vehicle
communications.
#
SUMMARY
25 [0004] This summary is provided to introduce concepts related to systems and
methods for channel resource allocation for device-to-device communication. This summary
is neither intended to identify features of the claimed subject matter nor is it intended for use
in determining or limiting the scope of the claimed subject matter.
[0005] In one implementation, a method for channel resource allocation for device-to-
30 device (D2D) communication, to a new D2D link comprising a new receiver and a new
2
transmitter is described. The method includes computing, by the new receiver, a cumulative
interference for each of one or more D2D sets, where each D2D set includes at least one
existing D2D link, and where each existing D2D link includes an existing transmitter and an
existing receiver communicating over channel resources allocated to the corresponding D2D
5 set. The method further includes the new receiver calculating a link signal to interference plus
noise ratio (SINR) for each of the one or more D2D sets based at least on transmission power
of the new transmitter and the cumulative interference caused by existing transmitters
associated with the D2D set to determine one or more objected D2D sets. Further, each of a
plurality of existing receivers calculates a group SINR based at least on interference caused
10 by the new transmitter and an existing level of interference caused by existing transmitters of
the D2D set associated with the existing receiver.
[0006] The method further includes transmitting, by -the new receiver, a D2D set
^ objection signal over objection phase channel resources allocated by a base station to the one
or more objected D2D sets to indicate an objection on usage of the channel resources
15 associated with the objected D2D sets by the new D2D link. The method further includes
transmitting, by an existing receiver, a D2D link objection signal to indicate an objection, on
joining of the D2D set associated with the existing receiver by the new D2D link for
allocation of channel resources based on a comparison of a threshold SINR with the group
SINR of the existing receiver. The objection signal is transmitted over objection phase
20 channel resources allocated by the base station to the D2D set associated with the existing
receiver. Further, the new transmitter determines one or more allowed D2D sets, from among
the one or more D2D sets, based on the D2D set objection signal and the D2D link objection
signal, for allocation of the channel resources associated with one of the allowed D2D sets for
D2D communication. The method further includes allocating, by the base station, the channel
resources associated with a selected D2D set to the new D2D link, where the selected D2D
set is selected from among the allowed D2D sets based on one or more selection parameters.
[0007] In another implementation, a method for channel resource allocation for
device-to-device (D2D) communication, to a new D2D link comprising a new receiver and a
new transmitter is described. The method includes computing, by the new receiver, a
30 cumulative interference for each of one or more D2D sets, where each D2D set includes at
least one existing D2D link, and where each existing D2D link includes an existing
transmitter and an existing receiver communicating over channel resources allocated to the
corresponding D2D set. The method further includes calculating, by the new receiver, a link
3
signal to interference plus noise ratio (SINR) for each of the one or more D2D sets based at
least on transmission power of the new transmitter and the cumulative interference caused by
existing transmitters associated with the D2D set. The method further includes comparing, by
the new receiver, the link SINR with the threshold SINR, for each of the one or more D2D
5 sets, to determine the one or more objected sets of D2D links, where the objected sets of D2D
links are not to be joined by the new D2D link. The method further includes transmitting, by
the new receiver, a D2D set objection signal to indicate an objection on using channel
resources associated with the objected D2D sets based on the comparing, where the D2D set
objection signal is transmitted over objection phase channel resources allocated to the one or
10 more objected D2D sets.
[0008] In another implementation, a method for channel resource allocation for
device-to-device (D2D) communication, to a new D2D link comprising a new receiver and a
new transmitter is described. The method includes computing, by each of a plurality of
existing receivers, interference caused by a second test signal transmitted by the new
15 transmitter over an initial set of channel resources allocated to a D2D set associated with the
existing receiver. The method further includes calculating, by each of the plurality of existing
receivers, a group SINR based at least on the interference caused by the new transmitter and
an existing level of interference caused by existing transmitters of the D2D set associated
with the existing receiver. The method further includes comparing, by each of the plurality of
20 existing receivers, the group SINR with a threshold SINR, to determine whether the channel
resources associated with the existing receiver are to be allocated to the new D2D link.
Further, the method comprise transmitting, by an existing receiver from among the plurality
of existing receivers, a D2D link objection signal to indicate an objection, by the existing
receiver, on allocation of the channel resources associated with the existing receiver based on
the comparing, where the objection signal is transmitted over objection phase channel
resources allocated by a base station to the D2D set associated with the existing receiver.
[0009] In yet another implementation, a user equipment, where the user equipment is
a new receiver establishing a new D2D link with a new transmitter for device-to-device
(D2D) communication in a cellular communication network is described. The user equipment
30 comprising a processor and an interference computation module coupled to the processor to
compute a cumulative interference for each of one or more D2D sets interacting over the
cellular communication network, where each D2D set includes at least one existing D2D link,
and where each existing D2D link includes an existing transmitter and an existing receiver
4
communicating over channel resources allocated to the corresponding D2D set. The user
equipment further comprises a signal to interference plus noise ratio (SINR) computation
module coupled to the processor to calculate a link SINR for each of the one or more D2D
sets based at least on transmission power of the new transmitter and the cumulative
5 interference caused by existing transmitters associated with the D2D set. The SINR
computation module further compares, for each of the one or more D2D sets, the link SINR
with a threshold SINR to determine objected sets of D2D links, where the objected sets of
D2D links are not to be joined by the new D2D link. The user equipment further includes an
interaction module coupled to the processor to transmit a D2D set objection signal to indicate
10 an objection on using channel resources associated with the objected D2D sets based on the
comparison, where the D2D set objection signal is transmitted over objection phase channel
resources allocated to the one or more objected D2D sets.
[0010] In yet another implementation, a user equipment, where the user equipment an
existing receiver part of an existing D2D link established in a cellular communication
15 network for device-to-device (D2D) communication is described. The user equipment
comprising a processor and an interference computation module coupled to the processor to
compute interference caused by a second test signal transmitted by a new transmitter over an
initial set of channel resources allocated to a D2D set associated with the existing receiver.
The user equipment further comprising a signal to interference plus noise ratio (SINR)
20 computation module coupled to the processor to calculate a group SINR based at least on
interference caused by the new transmitter and an existing level of interference caused by
existing transmitters of the D2D set associated with the existing receiver. The SINR
computation module further compares the group SINR with a threshold SINR. The user
equipment further comprising an interaction module coupled to the processor to transmit a
IQ^ D2D link objection signal to indicate an objection, by the existing receiver, on allocation of
channel resources corresponding to the D2D set associated with the existing receiver based
on the comparison, where the D2D link objection signal is transmitted over objection phase
channel resources allocated to the D2D set associated with the existing receiver.
[0011] In yet another implementation, a non-transitory computer-readable medium
30 having embodied thereon a computer program for executing a method for channel resource
allocation for device-to-device (D2D) communication, to a new D2D link comprising a new
receiver and a new transmitter is described. The method includes computing, by the new
receiver, a cumulative interference for each of one or more D2D sets, where each D2D set
5
includes at least one existing D2D link, and where each existing D2D link includes an
existing transmitter and an existing receiver communicating over channel resources allocated
to the corresponding D2D set. The method further includes calculating, by the new receiver, a
link signal to interference plus noise ratio (SINR) for each of the one or more D2D sets based
5 at least on transmission power of the new transmitter and the cumulative interference caused
by existing transmitters associated with the D2D set. The method further includes comparing,
by the new receiver, the link SINR with the threshold SINR, for each of the one or more D2D
sets, to determine the one or more objected sets of D2D links, where the objected sets of D2D
links are not to be joined by the new D2D link. The method further includes transmitting, by
10 the new receiver, a D2D set objection signal to indicate an objection on using channel
resources associated with the objected D2D sets based on the comparing, where the D2D set
objection signal is transmitted over objection phase channel resources allocated to the one or
^ ^ more objected D2D sets.
[0012] In yet another implementation, a non-transitory computer-readable medium
15 having embodied thereon a computer program for executing a method for channel resource
allocation for device-to-device (D2D) communication, to a new D2D link comprising a new
receiver and a new transmitter is described. The method includes computing, by each of a
plurality of existing receivers, interference caused by a second test signal transmitted by the
new transmitter over an initial set of channel resources allocated to a D2D set associated with
20 the existing receiver. The method further includes calculating, by each of the plurality of
existing receivers, a group SINR based at least on the interference caused by the new
transmitter and an existing level of interference caused by existing transmitters of the D2D
set associated with the existing receiver. The method further includes comparing, by each of
the plurality of existing receivers, the group SINR with a threshold SINR, to determine
^fb whether the channel resources associated with the existing receiver are to be allocated to the
new D2D link. Further, the method comprise transmitting, by an existing receiver from
among the plurality of existing receivers, a D2D link objection signal to indicate an objection,
by the existing receiver, on allocation of the channel resources associated with the existing
receiver based on the comparing, where the objection signal is transmitted over objection
30 phase channel resources allocated by a base station to the D2D set associated with the
existing receiver.
BRIEF DESCRIPTION OF THE FIGURES
[0013] The detailed description is described with reference to the accompanying
figures. In the figures, the left-most digit(s) of a reference number identifies the figure in
which the reference number first appears. The same numbers are used throughout the figures
5 to reference like features and components. Some embodiments of system or methods in
accordance with embodiments of the present subject matter are now described, by way of
example, and with reference to the accompanying figures, in which:
[0014] Fig. 1 illustrates a cell of a communication network implementing a system for
allocating channel resources for device-to-device communication in the communication
10 network, in accordance with an embodiment of the present subject matter;
[0015] Fig. 2 represents a call flow diagram indicating procedures of allocating
P channel resources for device-to-device communication in a cellular communication network,
in accordance with an embodiment of the present subject matter; and
[0016] Fig. 3 illustrates a method for allocating channel resources for device-to-
15 device communication in a cellular communication network, in accordance with an
embodiment of the present subject matter.
[0017] It should be appreciated by those skilled in the art that any block diagrams
herein represent conceptual views of illustrative systems embodying the principles of the
present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams,
20 state transition diagrams, pseudo code, and the like, represent various processes which may
be substantially represented in computer readable medium and so executed by a computer or
processor, whether or not such computer or processor is explicitly shown.
DESCRIPTION OF EMBODIMENTS
[0018] Systems and methods for channel resource allocation for device-to-device
25 (D2D) communication in a cellular communication network are described. D2D
communication, as will be understood, refers to wireless communication happening directly
between two or more communication devices. For instance, two communication devices in
proximity to each other may communicate directly with each other, instead of communicating
with each other via a base station. Transmitting data directly between two communication
30 devices facilitates reduction in transmission power consumption. Enhanced connectivity
7
using the D2D communication link allows the users to utilize data intensive multimedia
services, such as Push-to-X video calling, live media streaming, and online gaming.
[0019] In one approach, the D2D communications use a dedicated spectrum, which is
separate from the spectrum used by the conventional wireless networks, such as cellular
5 communication networks. Using a dedicated spectrum may, however, not be efficient in
terms of spectrum usage as network operators need to assign dedicated network resources for
the dedicated spectrum that cannot be dynamically shared and balanced with the regular
network routed users according to the availability of the spectrum.
[0020] In another conventional approach, alternate to using the dedicated licensed
10 spectrum, an unlicensed spectrum may be used for the D2D communication. Such an
approach of D2D communication however requires upgrading the communication devices to
^ operate in the unlicensed spectrum, thus affecting its acceptance and usage among users.
Further, absence of any central station for controlling the D2D communication affects the
service of quality of the D2D communication.
15 [0021] According to an implementation of the present subject matter, systems and
methods for channel resource allocation for D2D communication in a cellular communication
network are described. In one embodiment, two or more communication devices
communicating with each other over a cellular communication network, such as Long Term
Evolution (LTE) network or Wideband Code Division Multiple Access (WCDMA) network
20 may initiate a D2D communication in order to exchange data using channel resources
available in the cellular communication network. The present method for channel resource
allocation involves allocation of the same channel resources to one or more pairs of
communication devices, each pair of communication device being referred to as a D2D link.
A D2D link may thus include a transmitter and a receiver in direct communication with each
25 other. In one implementation, the D2D links are assigned the channel resources based on
Signal to Interference plus Noise Ratio (SINR) experienced by the D2D links on being
allocated the same channel resources. This ensures that there is no or minimal interference
between the communication devices.
[0022] According to one embodiment of the subject matter, various D2D links, may
30 be organized into one or more D2D sets such that all the D2D links associated with a
particular D2D set may use the same channel resources for D2D communication. A D2D set
8
•
may thus be defined as a group of one or more D2D links that can communicate using the
same channel resources. For example, a base station handling cellular communications in a
particular area, say, a cell may identify three available channel resources for D2D
communication for a given time period. The base station may further allocate channel
5 resources to various, say, ten D2D links thus forming one or more, say, three D2D sets. For
instance, five D2D links may be assigned to a first D2D set, three D2D links may be assigned
to a second D2D set, and two D2D links may be assigned to a third D2D set, such that D2D
links assigned to a particular D2D set can use the same channel resources.
[0023] In one implementation, the D2D links may be assigned to a particular D2D set
10 such that a D2D link assigned to a particular D2D set does not experience poor SINR due to
another D2D link assigned to the same D2D set. As will be understood, assigning a D2D link
to a D2D set means the D2D link is allocated the same channel resources as used by other
B' D2D links in that D2D set. For the purpose, when a pair of communication devices, say, a
transmitter and a receiver wishes to communicate with each other using D2D communication,
15 one of the communication devices may send a scheduling request to the base station for
allocation of initial channel resources to the communication devices for initiating a D2D set
selection process. For the sake of brevity, and not as a limitation, the pair of communication
devices trying to select the D2D set is hereinafter referred to as a new D2D link while the
transmitter and the receiver of the new D2D link are referred to as a new transmitter and a
20 new receiver, respectively. Further, transmitters and receivers already connected to the base
station for D2D communication are referred to as existing transmitters and existing receivers,
respectively, while the D2D links formed by the existing transmitters and existing receivers
are referred to as existing D2D links.
^ [0024] On receiving the scheduling request, the base station may allocate the initial
25 sets of channel resources to the new D2D link and the D2D sets, such that each D2D set is
allocated different initial channel resources. The existing transmitters of each of the D2D set
may subsequently transmit a first test signal over the initial channel resources allocated to the
corresponding D2D set. On receiving the first test signals, the new receiver may compute a
cumulative interference for each D2D set based on the first test signals transmitted by
30 existing transmitters associated with the particular D2D set. For instance, the new receiver
may determine the cumulative interference for the first D2D set based on existing
transmitters associated with the first D2D set.
9
[0025] Subsequently, the new transmitter may transmit a second test signal that may
be received by each of the existing receivers and used for computing a probable interference
caused by the second test signal, and in turn by the new transmitter. In one implementation,
the base station may allocate transmission phase channel resources to each of the D2D sets
5 and the new transmitter for the transmitting the second test signal. In another implementation,
the new transmitter may use the initial channel resources for transmitting the second test
signal. Upon computing the probable interference by the new transmitter, each existing
receiver may calculate a group SFNR by adding the probable interference to an existing level
of interference caused by the existing transmitters of the D2D set associated with the existing
10 receiver. In one implementation, the second test signal may also be received by the new
receiver and used for computing transmission power of the new transmitter. Upon computing
the transmission power, the new receiver may calculate a link SINR, for each D2D set, based
^ ^ on the transmission power and the cumulative interference associated with the D2D set.
[0026] The new receiver may subsequently compare the link SFNR of each D2D set,
15 with a predetermined threshold SINR to determine whether the SfNR of the new receiver is
affected by the joining of a D2D set by the new D2D link. Similarly, each of the existing
receivers may compare the corresponding group SFNR with the predetermined threshold
SFNR to determine whether the group SFNR is affected by the joining of the D2D set
associated with the existing receiver by the new D2D link. In one implementation, if the
20 group SFNR of any particular existing receiver is less than the threshold SFNR, then the
existing receiver may determine that it will experience interference if the new D2D link is
allocated the same channel resources that are allocated to the particular existing receiver. The
existing receiver in such a case may object to allocation of the channel resources associated
1 ^ with its D2D set to the new D2D link. Similarly, if the SFNR of the new receiver, for any
25 D2D set, is less than the threshold SFNR, then the new receiver may determine that it will
experience interference if the new D2D link is allocated the same channel resources that are
allocated to the D2D set. The new receiver in such a case may object to allocation of the
channel resources associated with the D2D set to the new D2D link and identify all such D2D
sets as objected D2D sets.
30 [0027] In one implementation, the existing receivers that object to allocation of the
channel resources associated with its D2D set to the new D2D link may transmit a D2D link
objection signal over objection phase channel resources allocated by the base station to the
10
D2D set to which the existing receiver belongs. The objection phase channel resources, in
one implementation may be allocated at the time of allocating the initial resources in response
to the scheduling request. In another implementation, the objection phase channel resources
may be allocated upon transmission of the second test signal by the new transmitter. Further,
in case the new receiver objects to allocation of the channel resources associated with a
particular D2D set, the new receiver may transmit a D2D set objection signal over objection
phase channel resources allocated to that particular D2D set. The new transmitter may
subsequently listen to objection phase resources allocated to all the D2D sets to determine
whether either the D2D link objection signal or the D2D set objection signal has been
transmitted on any of the objection phase channel resources. Based on the determination, the
new transmitter may identify all the objection phase channel resources on which neither the
D2D link objection signal nor the D2D set objection signal has been transmitted and identify
the D2D sets corresponding to the objection phase channel resources as allowed D2D sets.
[0028] In one implementation, upon identifying one or more allowed D2D sets, the
15 new transmitter may select one of the allowed D2D sets for channel allocation and request
the base station to allocate the channel resources associated with the selected D2D set to the
new D2D link for D2D communication. In another implementation, the new transmitter may
request the base station to select one of the allowed D2D sets for channel allocation and
allocate the channel resources associated with the selected D2D set to the new D2D link.
20 Further, upon determination of the selected D2D set, the base station may inform the new
receiver and the new transmitter about the selected D2D set to allow the new D2D link to
initiate the D2D communication over the channel resources associated with selected D2D set.
The base station may further inform the existing D2D links associated with the selected D2D
^ set about the addition of the new D2D link to the D2D set and allocation of the channel
/5 resources to the new D2D link so that the existing D2D links may update the existing
interference for their D2D set.
[0029] Further, in case the new transmitter determines that it may not be able to join
any of the existing D2D sets, the base station may allocate new channel resources, if
available, to the new D2D link thus forming a new D2D set.
30 [0030] The present subject matter thus facilitates channel resource allocation to the
new D2D link for D2D communication. Allowing the new D2D link to ascertain the channel
11
resources that may be allocated to it based on the SINR experienced by the new D2D link due
to the existing D2D links using the same channel resources facilitates in ensuring high level
of quality of service (QoS) to the new D2D link. Further, enabling the existing D2D links to
object to allocation of channel resources associated with the existing D2D link based on the
SfNR experienced by the existing D2D link due to the new D2D link facilitates in ensuring
that the QoS provided to the existing D2D links is not affected.
[0031] Thus, allocating the channel resources based on SINR experienced by new
D2D link and the existing D2D facilitates in allocating the same channel resources to a
plurality of D2D links for D2D communication at the same time. Further, organizing such
D2D links, which may be allocated the same channel resources, into a single D2D set
facilitates in dynamic bandwidth and channel resource allocation as the base station may now
allocate the channel resources to different D2D sets instead of each time determining the
D2D links that may be allocated the same channel resource. Such an allocation of channel
resources especially helps in scenarios where number of channel resources available for D2D
15 communication changes dynamically, for example, depending on traffic of communication
devices using the cellular communication network for conventional communication. Further,
facilitating the base station to control and schedule the channel resource allocation by way of
allocating the initial sets of channel resources and the objection phase channel resources
helps in ensuring better QoS as the base station may control time taken for the channel
20 resource allocation based on the number of available channel resources. For instance, the
base station may delay the channel resource allocation in scenarios where the number of
available channel resources is less due to increase in the communication traffic of
communication devices using the cellular communication network for conventional
^ ^ communication. The base station is thus enabled to allocate channel resources to a D2D set
z5 depending on QoS requirements of that D2D set, thus ensuring high network efficiency and
performance.
[0032] It should be noted that the description and figures merely illustrate the
principles of the present subject matter. It will thus be appreciated that those skilled in the art
will be able to devise various arrangements that, although not explicitly described or shown
30 herein, embody the principles of the present subject matter and are included within its spirit
and scope. Furthermore, all examples recited herein are principally intended expressly to be
for pedagogical purposes to aid the reader in understanding the principles of the present
12
subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to
be construed as being without limitation to such specifically recited examples and conditions.
Moreover, all statements herein reciting principles, aspects, and embodiments of the present
subject matter, as well as specific examples thereof, are intended to encompass equivalents
5 thereof
[0033] It will also be appreciated by those skilled in the art that the words during,
while, and when as used herein are not exact terms that mean an action takes place instantly
upon an initiating action but that there may be some small but reasonable delay, such as a
propagation delay, between the initial action and the reaction that is initiated by the initial
10 action. Additionally, the words "connected" and "coupled" are used throughout for clarity of
the description and can include either a direct connection or an indirect connection.
^ [0034] The manner in which the systems and the methods of channel resource
allocation for device-to-device communication may be implemented has been explained in
details with respect to the Figures 1 to 3. While aspects of described systems and methods for
15 channel resource allocation for device-to-device communication can be implemented in any
number of different computing systems and transmission environments, the embodiments are
described in the context of the following system(s).
[0035] Figure 1 illustrates a cell 100 of a communication network implementing a
system for allocating channel resources for device-to-device communication in the
20 communication network according to an embodiment of the present subject matter. In one
implementation, the communication network may be a cellular communication network, such
as LTE and WCDMA. The communication network includes one or more user equipments
communicating, with each other and a base station 102, over one or more channel resources
allocated by the base station 102 for D2D communication, in addition to cellular devices
25 communicating using the normal cellular communication protocols. D2D communication, as
will be understood, is a mode of communication used for communication between two user
equipments, say, a transmitter and a receiver proximate to each other.
[0036] The user equipments may be implemented as one or more of cellular phones,
smart phones, personal digital assistants (PDAs), portable computers, desktop computers,
30 tablet computers, phablets, and the like. Further, the user equipments include one or more
transmitters 104-1, 104-2, 104-3, 104-4, 104-5, 104-6, ..., 104-n, hereinafter collectively
13
•
referred to as transmitters 104 and individually referred to as transmitter 104, and one or
more receivers 106-1, 106-2, 106-3, 106-4, 106-5, 106-6, ..., 106-n, hereinafter collectively
referred to as receivers 106 and individually referred to as receiver 106. In one
implementation, each transmitter 104 may be communicating with a corresponding receiver
5 106 over the channel resources thus forming a pair of equipment devices, hereinafter referred
to as a D2D link. For instance, the transmitter 104-1 and the receiver 106-1 may
communicate with each other forming a D2D link 108-1. Similarly, the transmitter 104-2 and
the receiver 106-2 may form a D2D link 108-2, the transmitter 104-3 and the receiver 106-3
may form a D2D link 108-3, while the transmitter 104-n and the receiver 106-n may form a
10 D2D link 108-n. The D2D links 108-1, 108-2, 108-3, 108-4, 108-5, 108-6 ..., 108-n may be
hereinafter collectively referred to as D2D links 108 and individually referred to as D2D link
108.
A
^ [0037] According to an embodiment of the present subject matter, the base station
102 may organize the D2D links 108 into one or more D2D sets such that the D2D links 108
15 associated with a particular D2D set may use the same channel resources. Allocating the
same channel resources to one or more D2D links 108 facilitates D2D communication with
optimum utilization of channel resources as lesser number of resources may be used for
catering to a large number of users. For instance, the D2D link 108-2 and the D2D link 108-4
may be grouped into a first D2D set, the D2D link 108-3 and D2D link 108-6 may be
20 grouped into a second D2D set, and the D2D link 108-5 and the D2D link 108-n may be
grouped into a third D2D set. In one implementation, the base station 102 may create the
D2D sets such that no two D2D links 108 associated with the same set experience
interference or decrease in performance allocated the same channel resources for the D2D
1 ^ communication. Creating such D2D sets thus facilitates in dynamic channel resource
25 allocation as the base station may simply allocate the channel resources to different D2D sets
instead of each time determining the D2D links that may be allocated the same channel
resource.
[0038] Further, whenever a new pair of user equipments requests the base station 102
for allocation of channel resources, the base station 102 may initially either assign the new
30 pair of user equipments to one of the existing D2D sets or create a new set and then allocate
the channel resources associated with the D2D set allocated to the new pair of user
equipments. For the sake of brevity, and not as a limitation, the pair of communication
14
devices trying to select the D2D set is hereinafter referred to as a new D2D link 108 while the
transmitter and the receiver of the new D2D link are referred to as a new transmitter 104 and
a new receiver 106, respectively. Further, transmitters and receivers already connected to the
base station 102 are referred to as existing transmitters 104 and existing receivers 106,
5 respectively, while the D2D links formed by the existing transmitters 104 and the existing
receivers 106 are referred to as existing D2D links 108. For instance, as illustrated in the fig.
1, the transmitter 104-1 may be referred to as the new transmitter 104, while the transmitters
104-2, ..., 104-n may be referred to as the existing transmitters 104. The receiver 106- 1 may
be referred to as the new receiver 106, while the receivers 106-2, ..., 106-n may be referred
10 to as the existing receivers 106. The D2D link 108- 1 may be referred to as the new D2D link
108, while the D2D links 108-2, ..., 108-n may be referred to as the existing D2D links 108.
[0039] Further, the base station 102, the transmitters 104, and the receivers 106
^ ^ include processors 110-1, 110-2, and 110-3 respectively. The processors 110-1, 110-2, and
110-3, collectively referred to as processor 110 hereinafter, may be implemented as one or
15 more microprocessors, microcomputers, microcontrollers, digital signal processors, central
processing units, logic circuitries, and/or any devices that manipulate signals based on
operational instructions. Among other capabilities, the processor(s) is configured to fetch and
execute computer-readable instructions stored in the memory.
[0040] The functions of the various elements shown in the figure, including any
20 fiinctional blocks labeled as "processor(s)", may be provided through the use of dedicated
hardware as well as hardware capable of executing software in association with appropriate
software. When provided by a processor, the functions may be provided by a single dedicated
processor, by a single shared processor, or by a plurality of individual processors, some of
^ ^ which may be shared. Moreover, explicit use of the term "processor" should not be construed
25 to refer exclusively to hardware capable of executing software, and may implicitly include,
without limitation, digital signal processor (DSP) hardware, network processor, application
specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory
(ROM) for storing software, random access memory (RAM), non-volatile storage. Other
hardware, conventional and/or custom, may also be included.
30 [0041] The base station 102, the transmitters 104, and the receivers 106 include I/O
interface(s) (not shown in the figure) and memory (not shown in the figure). The I/O
interface(s) may include a variety of software and hardware interfaces that allow the base
15
station 102, the transmitters 104, and the receivers 106 to interact with each other. Further,
the I/O interfaces may enable the base station 102, the transmitters 104, and the receivers 106
to communicate with other communication and computing devices, such as web servers and
external repositories. The memory may be coupled to the processor 110 and may include any
5 computer-readable medium known in the art including, for example, volatile memory (e.g.,
RAM), and/or non-volatile memory (e.g., EPROM, flash memory, etc.).
[0042] The base station 102, the transmitters 104, and the receivers 106 further
include modules and data. The modules include routines, programs, objects, components,
data structures, and the like, which perform particular tasks or implement particular abstract
10 data types. The modules further include modules that supplement applications on the base
station 102, the transmitters 104, and the receivers 106, for example, modules of an operating
^ system. •
[0043] Further, the modules can be implemented in hardware, instructions executed
by a processing unit, or by a combination thereof The processing unit can comprise a
15 computer, a processor, such as the processor 110, a state machine, a logic array or any other
suitable devices capable of processing instructions. The processing unit can be a generalpurpose
processor which executes instructions to cause the general-purpose processor to
perform the tasks or, the processing unit can be dedicated to perform the fiinctions.
[0044] In another aspect of the present subject matter, the modules may be machine-
20 readable instructions (software) which, when executed by a processor/processing unit,
perform any of the described functionalities. The machine-readable instructions may be
stored on an electronic memory device, hard disk, optical disk or other machine-readable
storage medium or non-transitory medium. In one implementation, the machine-readable
instructions can be also be downloaded to the storage medium via a network connection. The
25 data serves, amongst other things, as a repository for storing data that may be fetched,
processed, received, or generated by one or more of the modules.
[0045] In an implementation, the modules of the base station 102 include a channel
resource allocation module 112. Similarly, in an implementation, the modules of each of the
transmitters 104 include a transmission module 114 and a selection module 116. Further, the
30 modules of each of the receivers 106 include an interaction module 118, an interface
computation module 120, and an SINK computation module 122.
16
[0046] In operation, in order to interact using D2D communication, the new D2D link
108 may establish a connection with the base station 102 to request for channel resource. As
described earlier, the base station 102 may initially assign the new D2D link 108 to an
existing D2D set and then allocate the channel resources associated with the D2D set to the
5 new D2D link 108. The new D2D link 108 may thus request the base station 102 to initiate a
D2D set selection process. For the purpose, either of the new transmitter 104 and the new
receiver 106 may send a scheduling request to the base station 102 for allocation of initial
channel resources to the new D2D link 108 and the existing D2D link 108 for initiating a
D2D set selection process. In one implementation, the new transmitter 104 and the new
10 receiver 106 may initially enter a D2D discovery process and communicate with each other,
say over conventional communication channels, to decide which one of the new transmitter
104 and the new receiver 106 may initiate the D2D selection process. One of the new
^ transmitter 104 and the new receiver 106 may subsequently send the scheduling request to the
base station 102. In one implementation, the scheduling request may include identifier
15 details, IP address of the new transmitter 104 and the new receiver 106 and level of QoS
desired by the new transmitter 104 and the new receiver 106. Further, for the purpose of
explanation and not as a limitation, we will assume that the new receiver 106 sends the
scheduling request to the base station 102. Thus, in one example, the interaction module 118
of the new receiver 106 may transmit the scheduling request to the base station 102.
20 [0047] On receiving the scheduling request, the channel resources allocation module
112 of the base station 102 may initially determine the number of D2D sets currently created
and then determine whether it has the channel resources for allocation to all the D2D sets. In
case the sufficient channel resources are not available, the base station 102 may delay the
D2D set selection process and inform the new receiver 106 accordingly. In case the channel
resources allocation module 112 determines that the channel resources currently available are
sufficient for allocation for the D2D set selection process, the channel resources allocation
module 112 may allocate the initial channel resources to the new D2D link 108 and the D2D
sets, such that each D2D set is allocated separate channel resources. For the purpose, the base
station 102 may send a resource grant message to the new receiver 106. The resource grant
30 message may include information about the initial channel resources allocated to each of the
D2D sets. In one implementation, the interaction module 118 of the new receiver 106 and the
transmission module 114 of the existing transmitters 104 may receive the resource grant
message.
17
[0048] Upon receiving the resource grant message, the new D2D links 108 and the
existing D2D links may enter into a listen phase. In the listen phase, the transmission module
114 of each of the existing transmitters 104 may transmit a first test signal over the initial
channel resources allocated to the corresponding D2D set. For instance, the transmission
5 module 114 of the existing transmitters 104-2 and 104-4 may send the first test signals over
the same initial channel resources. Further, all the existing transmitters 108 associated with
the same D2D set may transmit the first test signal on the corresponding channel resources at
the same time. In one implementation, the existing transmitters 104 of all the D2D sets may
send the first test signals at the same time over there respective channel resources. In another
10 implementation, the existing transmitters 104 different D2D sets may transmit the first test
signal in a sequential order based on a transmission schedule assigned by the base station
102.
A [0049] The first test signals may be received by the interaction module 118 of the new
receiver 106 and provided to the interference computation module 120 for further processing.
15 In one implementation, where all the existing transmitters transmit the first test signals at the
same time, the interaction module 118 of the new receiver 106 may identify the first test
signals corresponding to the same D2D sets and provide the first test signals corresponding to
the same D2D sets together. In another implementation, where the existing transmitters 104
different D2D sets transmit the first test signal in a sequential order, the interaction module
20 118 of the new receiver 106 may determine the D2D sets based on the transmission schedule
assigned by the base station 102 and inform the interference computation module 120
accordingly. The interference computation module 120 of the new receiver 106 may
subsequently compute a cumulative interference for each D2D set based on the first test
signals transmitted by existing transmitters 106 associated with the particular D2D set. The
interference computation module 120 of the new receiver 106 may determine the interference
based on the energy level in each of the first test signals and add the interference from the
existing transmitters 104 of a particular D2D set to ascertain the cumulative interference for
the D2D set. For instance, the interference computation module 120 of the new receiver 106
may determine the cumulative interference for the first D2D set based on the total energy in
30 the first test signals received from the existing transmitters 104-2 and 104-4. Further, it may
be understood that the new receiver 106 may not receive the first test signals of one or more
existing transmitters 104 positioned at far distance from the new receiver 106 and may thus
not consider those existing transmitters 104. Not considering such existing transmitters 104
18
may however not affect the set selection process as such existing transmitters 104 would not
affect the performance and QoS of the new D2D link 108.
[0050] Upon computation of the cumulative interference, the base station 102 may
initiate a transmission phase for calculation of possible interference caused by the new
5 transmitter 104 to the existing D2D links 108. In one implementation, the channel resource
allocation module 112 may allocate transmission phase channel resources to each of the D2D
sets and the new transmitter 104 for the transmission phase. In another implementation, the
channel resource allocation module 112 may instruct the D2D sets and the new transmitter
104 to use the initial channel resources for the transmission phase also. The transmission
10 module 114 of the new transmitter 104 may subsequently transmit a second test signal over
either the initial channel resources or the transmission phase channel resources of the D2D
sets such that the second test signal may be received by each of the existing receivers 106.
# [0051] Further, the second test signal may be received by the interaction module 118
of each of the existing receivers 106 and provided to the interference computation module
15 120 of each of the existing receivers 106 for further processing. The interference computation
module 120 of the existing receivers 106 may subsequently determine the interference caused
by the second test signal based on the energy level of the second test signal. Further, the
second test signal may also be received by the interaction module 118 of the new receiver
106 and provided to the SINR computation module 122 of the new receiver 106 for further
20 processing. The SINR computation module 122 of the new receiver 106 may then analyze the
second test signal to determine transmission power of the new transmitter 104.
[0052] The existing receivers 106 and the new receiver 106 may subsequently
calculate SINR experienced by them in the presence of the new transmitter 104 and the
W existing transmitters 104. In one implementation, the SINR computation module 122 of each
25 of the existing receivers 106 may calculate a group SINR for the existing receiver 106 by
adding the interference to an existing level of interference caused by the existing transmitters
104 of the D2D set associated with the existing receiver 106. The existing level of
interference may be pre-computed and available with the existing receivers 106 and thus need
not be calculated at the time group SINR computation. Each of the existing receivers 106
30 may subsequently determine whether the new D2D link 108 should be allowed join the D2D
set associated with the existing receiver 106 based on the group SINR. The SINR
computation module 122 of each of the existing receivers 106 may compare the group SINR
19
with a predetermined threshold SINR to determine whether the group SINR of the existing
receiver 106 is affected by the joining of the corresponding D2D set by the new D2D link
108. The predetermined threshold may be determined based on one or more factors, such as
desired rate of communication and robustness to channel variations. In one implementation, if
5 the group SINR of any particular existing receiver 106 is less than the threshold SINR, then
the SINR computation module 122 of the existing receiver 106 may determine that it will
experience interference if the new D2D link 108 is allocated the same channel resources that
are allocated to the particular existing receiver 108. The existing receiver 106 in such a case
may object to allocation of the channel resources associated with its D2D set to the new D2D
10 link 108. In case the SINR computation module 122 of the existing receiver 106 determines
the SINR to be equal to or greater than the threshold SINR, then SINR computation module
122 of the existing receiver 106 may allow the D2D link 108 to join the associated D2D set.
^ [0053] Further, the SINR computation module 122 of the new receiver 106 may
calculate a link SINR experienced by the new receiver 106, for each of the D2D sets, based
15 on the transmission power and the cumulative interference associated with the D2D set. The
SINR computation module 114 of the new receiver 106 may subsequently compare the link
SINR with the predetermined threshold SINR to determine whether it would experience
excessive interference from an existing D2D link 108 if the new D2D link 108 joins the D2D
set associated with the existing D2D link 108. In case the link SINR, for any D2D set, is less
20 than the threshold SINR, then the SINR computation module 114 of the new receiver 106
may determine that it will experience interference while using the same channel resources
that are allocated to the D2D set. The new receiver 106 may thus identify all such D2D sets
as objected D2D sets and object to joining these D2D sets for allocation of the channel
^ resources associated with the D2D set.
25 [0054] The new receiver 106 and the existing receivers 106 may subsequently initiate
an objection phase to indicate to the new transmitter 104 and their objections over the new
D2D link 108 joining one or more D2D sets based on the comparison of the link SINR and
the group SINR, respectively, with the predetermined threshold. In one implementation, the
channel resource allocation module 112 may allocate objection phase channel resources to
30 each of the D2D sets for the objection phase and provide information about the objection
phase channel resources to the new transmitter 104. Upon being allocated the objection phase
channel resources, the new transmitter 104 may listen to objection phase resources allocated
20
to all the D2D sets to determine whether an objection signal has been transmitted on any of
the objection phase channel resources by either the new receiver 106 or any of the existing
receivers 106. For instance, the interaction module 118 of the existing receivers 106 that
object to joining of its D2D set by the new D2D link 108 for allocation of the channel
5 resources may transmit a D2D link objection signal over the objection phase channel
resources allocated to the D2D set to which the existing receiver 106 belongs. Further, the
interaction module 118 of the new receiver 106 may transmit a D2D set objection signal over
the objection phase channel resources allocated to the objected D2D sets identified in the
transmission phase.
10 [0055] In case the selection module 116 of the new transmitter 104 detects either the
D2D link objection signal or the D2D set objection signal over the objection phase channel
^ resources of a particular D2D set, the selection module 116 may mark the corresponding
" D2D set as a rejected D2D set. Further, the D2D sets associated with the objection phase
channel resources on which neither the D2D link objection signal nor the D2D set objection
15 signal has been transmitted may be marked as allowed D2D sets by the selection module 116
of the new transmitter 104.
[0056] Upon identifying one or more allowed D2D sets, the new transmitter 104 may
initiate a selection phase for selecting one of the allowed sets for joining in order to be
allocated the channel resources associated with the D2D set. In one embodiment, the
20 selection module 116 of the new transmitter 104 may select one of the allowed D2D sets for
channel allocation and send a channel selection message to the base station 102 for allocation
of the channel resources associated with the selected D2D set to the new D2D link for D2D
communication. For instance, in case one or more D2D sets are determined as allowed D2D
V sets, the selection module 116 of the new transmitter 104 may select one of the allowed D2D
25 sets as a selected D2D set. In one implementation, the selection module 116 of the new
transmitter 104 may determine the selected D2D set based on or more selection parameters,
such as number of existing D2D links 108 associated with a D2D set, time duration for which
the D2D set has been set up, and SINK of the new D2D link 108 in the D2D set. Further, in
case only one allowed D2D set has been identified, the selection module 116 of the new
30 transmitter 104 may send the channel selection message to the base station 102 for allocation
of the channel resources associated with the selected D2D set.
21
[0057] In another embodiment, the selection module 116 of the new transmitter 104
may request the base station 102 to select one of the allowed D2D sets for channel allocation.
In said embodiment, the channel selection message sent by the selection module 116 of the
new transmitter 104 may include a list of the allowed D2D sets. The channel resource
5 allocation module 112 in such a case may determine one of the allowed D2D sets as the
selected D2D set based on the selection parameters. Upon determination of the selected D2D
set, the base station 102 may inform the new D2D link 108 about the selected D2D set to
allow the new D2D link 108 to initiate the D2D communication over the channel resources
associated with selected D2D set. In one implementation, the channel resource allocation
10 module 112 may send a set allocation message to the new receiver 106 and the new
transmitter 104 having information of the selected D2D set. The channel resource allocation
module 112 may further send the set allocation message to the existing D2D links 108
associated with the selected D2D set to inform the existing D2D links 108 about the addition
of the new D2D link 108 to the D2D set so that the existing D2D links 108 may update the
15 existing interference and SINR for their D2D set.
[0058] Further, in case the selection module 116 of the new transmitter 104 detects
either the D2D link objection signal or the D2D set objection signal over the objection phase
channel resources of all the D2D sets, the new transmitter 104 may determine that it may not
be able to join any of the existing D2D sets. The selection module 116 of the new transmitter
20 104 in such a case may send the channel selection message to the base station 102 to request
the base station 102 to allocate new channel resources, if available, to the new D2D link 108
thus forming a new D2D set.
[0059] Upon being assigned to a D2D set, the new transmitter 104 may initiate D2D
^ communication with the new receiver 106. In one implementation, the channel resource
25 allocation module 112 may transmit a channel resource allocation message to the new
transmitter 104 and the new receiver 106 to provide them the information about the channel
resources allocated to the selected D2D set. Further, in case the channel resource allocation
module 112 assigns new channel resources to the D2D set, the channel resource allocation
module 112 may transmit the channel resource allocation message to the existing D2D links
30 108 as well as the new D2D link 108. For instance, owing to the change in traffic and channel
resources requirements in the communication network, the channel resource allocation
module 112 may assign new channel resources to the D2D set. Upon receiving the channel
22
resource allocation message, the new transmitter 104 may identify the allocated channel
resources and transmit data to the new receiver 106 over the allocated channel resources.
[0060] Fig. 2 represents a call flow diagram 200 indicating procedures of allocating
channel resources for D2D communication in a cellular communication network, in
5 accordance with an embodiment of the present subject matter. The various arrow indicators
used in the call-flow diagram 200 depict the transfer of signal/information between the user
equipments and an eNodeB (eNB) 202 acting as the base station 102. In many cases, multiple
network entities besides those shown may lie between the entities, including transmitting
stations, and switching stations, although those have been omitted for clarity. Similarly,
10 various acknowledgement and confirmation network responses may also be omitted for
clarity. Although the description of Fig.2 has been made in considerable detail with respect to
an LTE network, it will be understood that the procedures of allocating channel resources for
m D2D communication may implemented for other networks as well, albeit with few
modifications.
15 [0061] The call flow diagram 200, as described in the Fig. 2 has been explained in
considerable details with respect to the new transmitter 104 initiating the procedure. It will be
understood that the principles described herein may be extended to various other scenarios as
well, for example, where the new receiver 106 initiates the procedure.
[0062] In one implementation, the of allocating channel resources for D2D
20 communication is initiated with the new transmitter 104 sending a scheduling request 204 to
the eNB 202 requesting the eNB 202 for allocation of channel resources to the new receiver
106 and the existing D2D link 108 for scheduling a D2D set selection process. The
scheduling request 204 may include details, such as IP address of the new transmitter 104 and
the new receiver 106 and desired QoS for D2D communication. The eNB 202 subsequently
transmits one or more resource grant messages 206-1, 206-2, and 206-3, hereinafter
collectively referred to as resource grant messages 206 and individually referred to as
resource grant message 206, to the new transmitter 104, the new receiver 106, and the
existing D2D links 108, respectively. The resource grant message 206 may include
information, such as information about various channels resources to be used by the new
30 transmitter 104, and the existing D2D links 108 for the D2D set selection process. For
instance, the resource grant message 206 may include information about the initial channel
resources, the transmission phase channel resources, and objection phase channel resources
allocated to each of the D2D sets.
23
[0063] Each of the existing transmitters 104 may subsequently transmit first test
signals 208-1, 208-2,..., 208-n over the initial channel resources allocated to the
corresponding D2D set. On receiving the first test signals 208-1, 208-2,..., 208-n, the new
receiver 106 may determine a cumulative interference from each of the existing transmitters
5 104. The eNB 202 may then initiate a transmission phase for calculation of possible
interference caused by the new transmitter 104 to the existing D2D links 108. In said phase
the new transmitter 104 transmits a second test signal 210 over the transmission phase
channel resources. Upon receiving the second test signal 210, the existing receivers 106 may
calculate corresponding group SINR based on interference caused by the second test signal
10 210 and an existing level of interference caused by the existing transmitters 104 of the D2D
set associated with the existing receiver 106. The existing receivers 106 may subsequently
compare the group SfNR with a predetermined threshold SINR to determine whether the
SINR of the existing receiver 106 is affected by the joining of a D2D set by the new D2D
link 108. The existing receivers 106 that object to allocation of the channel resources
15 associated with its D2D set to the new D2D link 108 may then transmit a D2D link objection
signal 212 over the objection phase channel resources allocated to the D2D set to which the
existing receiver 106 belongs.
[0064] Further, the new receiver 106 may calculate the transmission power of the new
transmitter 106 based on the second test signal 210 and compute the link SINR, for each D2D
20 set, based on the transmission power and the cumulative interference corresponding to the
D2D set. The new receiver 106 may subsequently compare the link SINR, for each D2D set,
with the predetermined threshold SINR to determine whether it will experience excessive
interference on the new D2D link 108 joining the D2D set. The new receiver 106 may then
transmit a D2D set objection signal 214 over objection phase channel resources allocated by
B the base station to the objected D2D sets determined based on the comparison of the link
SrSTR with the predetermined SINR.
[0065] The new transmitter 104 may subsequently listen to objection phase resources
allocated to all the D2D sets to determine whether either the D2D link objection signal 212 or
the D2D set objection signal 214 has been transmitted on any of the objection phase channel
30 resources. Based on the determination, the new transmitter 104 may identify one or more
allowed D2D sets and send a channel selection message 216 to the eNB 202. In one
embodiment, the channel selection message 216 may include an ID of a D2D set selected
from the one or more allowed D2D sets for channel resource allocation. In another
24
embodiment, the channel selection message may include a list of the allowed D2D sets
requesting the eNB 202 to select one of the D2D sets. The eNB 202 may subsequently send
set allocation messages 218-1, 218-2, and 218-3 to the new transmitter 104, the existing D2D
links 108, and the new receiver 106, respectively. The set allocation messages 218-1, 218-2,
5 and 218-3 may include information of the selected D2D set identified for addition of the new
D2D link 108. The eNB 202 may further transmit a channel resource allocation message 220
to the new transmitter 104 and the new receiver 106 to provide them the information about
the channel resources allocated to the selected D2D set. Upon receiving the channel resource
allocation message, the new transmitter 104 may initiate D2D communication with the new
10 receiver 106 by sending a data packet 222. On receiving the data packet 222 the new receiver
106 may send an acknowledgment message 224 to the new transmitter.
[0066] Fig. 3 illustrates a method 300 for channel resource allocation for D2D
m communication, according to an embodiment of the present subject matter. The order in
which the method is described is not intended to be construed as a limitation, and any number
15 of the described method blocks can be combined in any order to implement the method 300
or any alternative methods. Additionally, individual blocks may be deleted from the method
without departing from the spirit and scope of the subject matter described herein.
Furthermore, the method(s) can be implemented in any suitable hardware, software,
firmware, or combination thereof
20 [0067] The method may be described in the general context of computer executable
instructions. Generally, computer executable instructions can include routines, programs,
objects, components, data structures, procedures, modules, functions, etc., that perform
particular functions or implement particular abstract data types. The method may also be
^ practiced in a distributed computing environment where fiinctions are performed by remote
25 processing devices that are linked through a communications network. In a distributed
computing environment, computer executable instructions may be located in both local and
remote computer storage media, including memory storage devices.
[0068] A person skilled in the art will readily recognize that steps of the method 300
can be performed by programmed computers. Herein, some embodiments are also intended to
30 cover program storage devices or computer readable medium, for example, digital data
storage media, which are machine or computer readable and encode machine-executable or
computer-executable programs of instructions, where said instructions perform some or all of
25
the steps of the described method. The program storage devices may be, for example, digital
memories, magnetic storage media, such as a magnetic disks and magnetic tapes, hard drives,
or optically readable digital data storage media. The embodiments are also intended to cover
both communication network and communication devices to perform said steps of the
5 method(s).
[0069] At block 302, one of a new transmitter and a new receiver, transmits a
scheduling request to a base station for scheduling a D2D set selection process. For instance,
when a new D2D link, comprising of the new transmitter and the new receiver, enters a
cellular communication network for D2D communication, the new D2D link may establish a
10 connection with the base station to request for channel resource. In one implementation, the
base station may initially assign the new D2D link to an existing D2D set and then allocate
^ the channel resources associated with the D2D set to the new D2D link. Thus either the new
B
^ transmitter or the new receiver may send the scheduling request to the base station.
[0070] At block 304, the new transmitter and the new receiver receive a resource
15 grant message from the base station. In one implementation, one receiving the scheduling
request the base station, say, the base station 102 may allocate one or more initial channel
resources to each of the D2D set. The base station 102 may the send a resource grant
message, having information about the initial sets of channel resources allocated to one or
more D2D sets, to each of the existing D2D links and the new D2D link.
20 [0071] At block 306, the new receiver calculates a cumulative interference for each
D2D set. Upon allocation of the initial channel resources, existing transmitters associate with
the D2D sets may transmit a first test signal on the initial channel resources associated with
^ the corresponding D2D set. On receiving the first test signals from the existing transmitters,
the new receiver may calculate the cumulative interference for each D2D set.
25 [0072] At block 308, the new receiver calculates a link signal to interference plus
noise ratio (SINR) for each D2D set. In one implementation, the new receiver may initially
determine transmission power of the new transmitter based on a second test signal
transmitted by the new transmitter. Based on transmission power and the cumulative
interference corresponding to the D2D set the link SINR may then be calculated to determine
30 one or more objected D2D sets. The objected sets may be understood as the D2D sets which
the new receiver does not whish to join due to probable excessive interference from the
26
* 1.
existing transmitters associated with the D2D set. In one implementation, a D2D set may be
determined as an objected set if the link SINR of the new receiver reduces below a threshold
SINR.
[0073] At block 310, each of a plurality of existing receivers calculates a group SINR.
5 In one implementation, each of the existing receivers initially determines interference caused
by the second test signal transmitted by the new transmitter. Based on the interference caused
by the new transmitter and an existing level of interference caused by the existing
transmitters of the D2D set associated with the existing receiver, the group SINR may then be
calculated. The existing receivers may the compare the group SINR with the threshold SINR
10 to determine whether the new D2D link to be allowed to join the D2D set associated with the
existing receiver.
1^ [0074] At block 312, a D2D link objection signal may be transmitted by an existing
receiver that objects to the new D2D link joining the D2D set associated with the existing
receiver for allocation of channel resources. In one implementation, if the group SFNR of an
15 existing receiver decreases below the threshold SINR, then the existing receiver may transmit
the D2D link objection signal over objection phase channel resources allocated by the base
station to the D2D set associated with the existing receiver.
[0075] At block 314, a D2D set objection signal is transmitted transmit by the new
receiver over objection phase channel resources allocated to the one or more objected D2D.
20 [0076] At block 316, the new transmitter may determine one or more allowed D2D
sets, from among the one or more D2D sets. In one implementation, the new transmitter may
listen to the objection phase channel resources corresponding to each of the D2D sets to
9 determine whether any of the existing receivers and the new receiver has transmitted the D2D
set objection signal and the D2D link objection signal. On ascertaining the objection phase
25 channel resources over which neither of the D2D set objection signal and the D2D link
objection signal has been transmitted, the new transmitter may determine the corresponding
D2D sets as the allowed D2D sets that may be joined by the new D2D link for allocation of
the channel resources associated with one of the allowed D2D Sets.
[0077] At block 318, the channel resources associated with a selected D2D set are
30 allocated to the new D2D link by the base station. In one implementation, the selected D2D
27
i -u
set may be determined from among the allowed D2D sets by the new transmitter. In another
implementation, the selected D2D set may be determined from among the allowed D2D sets
by the base station. Further, the selected D2D set may be selected based on one or more
predetermined selection parameters.
[0078] Although embodiments for channel resource allocation for D2D
communication have been described in a language specific to structural features or
method(s), it is to be understood that the invention is not necessarily limited to the specific
features or method(s) described. Rather, the specific features and methods are disclosed as
embodiments for channel resource allocation for D2D communication.
28

1/We claim:
1. A method for channel resource allocation for device-to-device (D2D) communication,
to a new D2D link comprising a new receiver (106) and a new transmitter (104), the method
comprising:
5 computing, by the new receiver (106), a cumulative interference for each of
one or more D2D sets, wherein each D2D set includes at least one existing D2D link,
and wherein each existing D2D link includes an existing transmitter (104) and an
existing receiver (106) communicating over channel resources allocated to the
corresponding D2D set;
10 calculating, by the new receiver (106), a link signal to interference plus noise
ratio (SINR) for each of the one or more D2D sets based at least on transmission
power of the new transmitter (104) and the cumulative interference caused by existing
W transmitters (104) associated with the D2D set to determine one or more objected
D2D sets;
15 calculating, by each of a plurality of existing receivers (106), a group SINR
based at least on interference caused by the new transmitter (104) and an existing
level of interference caused by existing transmitters (104) of the D2D set associated
with the existing receiver (106);
transmitting, by the new receiver (106), a D2D set objection signal over
20 objection phase channel resources allocated by a base station (102) to the one or more
objected D2D sets, to indicate an objection, by the new D2D link, on using channel
resources associated with the objected D2D sets;
transmitting, by an existing receiver (106), a D2D link objection signal to
^ indicate an objection, on joining by the new D2D link, the D2D set associated with
?5 the existing receiver (106) for allocation of channel resources based on a comparison
of a threshold SINR with the group SINR of the existing receiver (106), wherein the
objection signal is transmitted over objection phase channel resources allocated by the
base station (102) to the D2D set associated with the existing receiver (106);
determining, by the new transmitter (104), one or more allowed D2D sets,
30 from among the one or more D2D sets, based on the D2D set objection signal and the
D2D link objection signal, for allocation of the channel resources associated with one
of the allowed D2D sets for D2D communication; and
29
allocating, by the base station (102), the channel resources associated with a
selected D2D set to the new D2D link, wherein the selected D2D set is selected from
among the allowed D2D sets based on one or more selection parameters.
2. The method as claimed in claim 1 further comprising:
5 transmitting, by one of the new transmitter (104) and the new receiver (106), a
scheduling request to the base station (102) for allocating initial channel resources for
initiating a channel selection process for determining the allowed D2D set; and
receiving, by the new transmitter (104) and the new receiver (106), a resource
grant message transmitted by the base station (102), wherein the resource grant
10 message includes information of the initial sets of channel resources allocated to each
of the one or more D2D sets and the new transmitter (104) and the new receiver (106)
for the channel selection process.
B 3. The method as claimed in claim 1, wherein the computing further comprises
receiving, by the new receiver (106), one or more first test signals over initial channel
15 resources allocated to the one or more D2D sets for computing the cumulative interference,
and wherein the cumulative interference for a particular D2D set is comf)uted based on the
first test signals transmitted by the existing transmitters (104) associated with the particular
D2D set.
4. The method as claimed in claim 1 further comprising:
20 transmitting, by the new transmitter (104), a second test signal transmitted
over each of the initial sets of channel resources;
receiving, by each of the existing receivers (106), the second test signal over
the initial set of channel resources associated with the existing receiver (106); and
computing, by each of the existing receivers (106), interference caused by the
second test signal received over the initial set of channel resources associated with the
existing receiver (106).
5. The method as claimed in claim 1 further comprising:
receiving, by the new receiver (106), a second test signal transmitted by the
new transmitter (104); and
30 computing, by the new receiver (106), transmission power of the new
transmitter (104) based on the second test signal.
30
6. The method as claimed in claim 1 further comprising comparing, by the new receiver
(106), the link SINR with the threshold SINR, for each of the one or more D2D sets, to
determine the one or more objected sets of D2D links.
7. The method as claimed in claim 1 further comprising allocating, by the base station
5 (102), new channel resources to the new D2D link upon determining, by the new transmitter
(104), each of the one or more D2D set to be an objected D2D set, wherein the new channel
resources are separate from the channel resources associated with the one or more D2D sets.
8. A method for channel resource allocation for device-to-device (D2D) communication,
to a new D2D link comprising a new receiver (106) and a new transmitter (104), the method
10 comprising:
computing, by the new receiver (106), a cumulative interference for each of
one or more D2D sets, wherein each D2D set includes at least one existing D2D link,
and wherein each existing D2D link includes an existing transmitter (104) and an
existing receiver (106) communicating over channel resources allocated to the
15 corresponding D2D set;
calculating, by the new receiver (106), a link signal to interference plus noise
ratio (SINR) for each of the one or more D2D sets based at least on transmission
power of the new transmitter (104) and the cumulative interference caused by existing
transmitters (104) associated with the D2D set;
20 comparing, by the new receiver (106), the link SINR with the threshold SINR,
for each of the one or more D2D sets, to determine the one or more objected sets of
D2D links, wherein the objected sets of D2D links are not to be joined by the new
D2D link; and
transmitting, by the new receiver (106), a D2D set objection signal to indicate
an objection on using channel resources associated with the objected D2D sets based
on the comparing, wherein the D2D set objection signal is transmitted over objection
phase channel resources allocated to the one or more objected D2D sets.
9. The method as claimed in claim 8 further comprising:
calculating, by each of a plurality of existing receivers (106), a group SINR based at
30 least on interference caused by the new transmitter (104) and an existing level of interference
caused by existing transmitters (104) of the D2D set associated with the existing receiver
(106);
31
< >
transmitting, by an existing receiver (106), a D2D link objection signal to
indicate an objection, by the existing receiver (106), on allocation of channel
resources corresponding to the D2D set associated with the existing receiver (106)
based on a comparison of the threshold SINR with the group SINR of the existing
5 receiver (106), wherein the objection signal is transmitted over objection phase
channel resources allocated by the base station (102) to the D2D set associated with
the existing receiver (106);
determining, by the new transmitter, one or more allowed D2D sets, from
among the one or more D2D sets, based on the D2D set objection signal and the D2D
10 link objection signal, for allocation of the channel resources associated with one of the
allowed D2D sets for D2D communication; and
allocating, by the base station (102), the channel resources associated with a
selected D2D set to the new D2D link, wherein the selected D2D set is chosen from
among the allowed D2D sets based on one or more selection parameters.
15 10. A method for channel resource allocation for device-to-device (D2D) communication,
to a new D2D link comprising a new receiver (106) and a new transmitter, the method
comprising:
computing, by each of a plurality of existing receivers (106), interference
caused by a second test signal transmitted by the new transmitter (104) over an initial
20 set of channel resources allocated to a D2D set associated with the existing receiver
(106);
calculating, by each of the plurality of existing receivers (106), a group signal
to interference plus noise ratio (SENR) based at least on the interference caused by the
new transmitter (104) and an existing level of interference caused by existing
transmitters (104) of the D2D set associated with the existing receiver (106);
comparing, by each of the plurality of existing receivers (106), the group
SINR with a threshold SFNR, to determine whether the channel resources associated
with the existing receiver (106) are to be allocated to the new D2D link; and
transmitting, by an existing receiver (106) from among the plurality of existing
30 receivers (106), a D2D link objection signal to indicate an objection, by the existing
receiver, on allocation of the channel resources associated with the existing receiver
(106) based on the comparing, wherein the objection signal is transmitted over
32
t >
objection phase channel resources allocated by a base station (102) to the D2D set
associated with the existing receiver.
11. A user equipment, wherein the user equipment is a new receiver (106) establishing a
new D2D link with a new transmitter (104) for device-to-device (D2D) communication in a
5 cellular communication network, the user equipment comprising:
a processor (110);
an interference computation module (120) coupled to the processor (110) to
compute a cumulative interference for each of one or more D2D sets interacting over
the cellular communication network, wherein each D2D set includes at least one
10 existing D2D link, and wherein each existing D2D link includes an existing
transmitter (104) and an existing receiver (106) communicating over channel
resources allocated to the corresponding D2D set;
a signal to interference plus noise ratio (SESfR) computation module (122)
coupled to the processor (110) to:
15 calculate a link SINR for each of the one or more D2D sets based at
least on transmission power of the new transmitter (104) and the cumulative
interference caused by existing transmitters (104) associated with the D2D set;
and
compare, for each of the one or more D2D sets, the link SINR with a
20 threshold SfNR to determine objected sets of D2D links, wherein the objected
sets of D2D links are not to be joined by the new D2D link; and
an interaction module (118) coupled to the processor (110) to transmit a D2D
set objection signal to indicate an objection on using channel resources associated
with the objected D2D sets based on the comparison, wherein the D2D set objection
signal is transmitted over objection phase channel resources allocated to the one or
more objected D2D sets.
12. The user equipment as claimed in claim 11, wherein the interaction module (118)
further:
transmits a scheduling request to a base station (102) for allocating initial sets
30 of channel resources for initiating a channel selection process for determining one or
more allowed D2D sets, from among the one or more D2D sets, for allocation of the
channel resources associated with one of the allowed D2D sets for D2D
communication;
33
^ y
receives a resource grant message transmitted by the base station (102),
wherein the resource grant message includes information of the initial sets of channel
resources allocated to each of the one or more D2D sets and the new transmitter (104)
and the new receiver (106) for the channel selection process; and
5 receives one or more first test signals over each of the initial sets of channel
resources for computing the cumulative interference, wherein the cumulative
interference for a particular D2D set is computed based on the first test signals
transmitted by the existing transmitters (104) associated with the particular D2D set.
13. A user equipment, wherein the user equipment is an existing receiver (106) part of an
10 existing D2D link established in a cellular communication network for device-to-device
(D2D) communication, the user equipment comprising:
a processor (110);
m an interference computation module coupled (120) to the processor (110) to
compute interference caused by a second test signal transmitted by a new transmitter
15 (104) over an initial set of channel resources allocated to a D2D set associated with
the existing receiver;
a signal to interference plus noise ratio (SINR) computation module (122)
coupled to the processor (110) to:
calculate a group SINR based at least on interference caused by the
20 new transmitter (104) and an existing level of interference caused by existing
transmitters (104) of the D2D set associated with the existing receiver (106);
and
compare the group SINR with a threshold SINR; and
an interaction module (118) coupled to the processor (110) to transmit a D2D
Ps link objection signal to indicate an objection, by the existing receiver (106), on
allocation of channel resources corresponding to the D2D set associated with the
existing receiver (106) based on the comparison, wherein the D2D link objection
signal is transmitted over objection phase channel resources allocated to the D2D set
associated with the existing receiver (106).
30 14. A non-transitory computer-readable medium having embodied thereon a computer
program for executing a method for channel resource allocation for device-to-device (D2D)
communication, to a new D2D link comprising a new receiver (106) and a new transmitter,
the method comprising:
34
< >•
computing, by the new receiver (106), a cumulative interference for each of
one or more D2D sets, wherein each D2D set includes at least one existing D2D link,
and wherein each existing D2D link includes an existing transmitter (104) and an
existing receiver (106) communicating over channel resources allocated to the
5 corresponding D2D set;
calculating, by the new receiver (106), a link signal to interference plus noise
ratio (SINR) for each of the one or more D2D sets based at least on transmission
power of the new transmitter (104) and the cumulative interference caused by the
existing transmitters (104) associated with the D2D set;
10 comparing, by the new receiver (106), the link SINR with the threshold SINR,
for each of the one or more D2D sets, to determine the one or more objected sets of
D2D links, wherein the objected sets of D2D links are not to be joined by the new
D2D link; and
transmitting, by the new receiver (106), a D2D set objection signal to indicate
15 an objection on using channel resources associated with the objected D2D sets based
on the comparing, wherein the D2D set objection signal is transmitted over objection
phase channel resources allocated to the one or more objected D2D sets.
15. A non-transitory computer-readable medium having embodied thereon a computer
program for executing a method for channel resource allocation for device-to-device (D2D)
20 communication, to a new D2D link comprising a new receiver (106) and a new transmitter
(104), the method comprising:
computing, by each of a plurality of existing receivers (106), interference
caused by a second test signal transmitted by the new transmitter (104) over an initial
set of channel resources allocated to a D2D set associated with the existing receiver
(106);
calculating, by each of the plurality of existing receivers (106), a group SINR
based at least on the interference caused by the new transmitter (104) and an existing
level of interference caused by existing transmitters (104) of the D2D set associated
with the existing receiver (106);
30 comparing, by each of the plurality of existing receivers (106), the group
SINR with a threshold SINR, to determine whether the channel resources associated
with the existing receiver (106) are to be allocated to the new D2D link; and
35
•y, yt
transmitting, by an existing receiver (106) from among the plurality of existing
receivers (106), a D2D link objection signal to indicate an objection, by the existing
receiver (106), on allocation of the channel resources associated with the existing
receiver (106) based on the comparing, wherein the objection signal is transmitted
over objection phase channel resources allocated by a base station (102) to the D2D
set associated with the existing receiver (106).