FIELD OF INVENTION
[0001] The present subject matter relates to device to device (D2D) communication and,
particularly, but not exclusively, to D2D discovery.
BACKGROUND
[0002] Over the years, there has been an exponential increase in the number of users
availing communication services offered by a service provider over communication networks.
The users typically avail such services using user devices, such as cellular phones, smart phones,
personal digital assistants (PDAs), portable computers, and desktop computers. However, with
the increase in the number of users, the network traffic exchanged over the communication
network has also increased significantly. With advancement in technology, alternate
communication techniques, such as device-to-device (D2D) communication have been
developed for reducing network traffic and providing efficient mode of data transfer without
incurring network usage charges. The D2D communication concerns wireless communications
directly between two user devices. For example, WiFi Direct is a technique by which devices can
directly communicate over WiFi channels without any intermediary network elements.
SUMMARY
[0003] This summary is provided to introduce concepts related to device to device (D2D)
communication. This summary is not intended to identify essential features of the claimed
subject matter nor is it intended for use in determining or limiting the scope of the claimed
subject matter.
[0004] In one implementation, a method for device to device discovery is described. The
method includes receiving a service request from a service availing device seeking to avail at
least one service, wherein the service request indicates the at least one service. The method
further comprises providing a link message to the service availing device and at least one service
offering device associated with the at least one service, based on the service request, for
initiating device discovery to establish a D2D link for availing the at least one service. Further, a
registration request from each of the one or more service offering devices is received, wherein
the registration request includes at least one of an identity credentials, service name, and service

3

information, and wherein the service information includes at least one of a name, a type, a
quality of service, and a service discovery range. The method further comprises registering each
of the one or more service offering devices based on the corresponding identity credentials
included in the registration request. Further, a service list including service details of one or more
services offered by the one ore more service offering devices registered with the base station is
broadcasted, wherein each of the one or more services is provided by one or more service
offering devices associated with the service.
[0005] In another implementation, a method for establishing a device to device link is
described. The method comprises providing a service request for availing at least one service to a
base station, wherein the service request indicates the at least one service. The method further
comprises receiving a link message for initiating device discovery with at least one service
offering device associated with the at least one service based on the service request. Further, a
service list including service details of one or more services is obtained, wherein each of the one
or more services is provided by one or more service offering devices associated with the service.
The method further comprises, sending a registration request for registering with the base station,
wherein the registration request includes at least one of an identity credentials, service name, and
service information, and wherein the service information includes at least one of a name, a type,
a quality of service, and a service discovery range.
[0006] In another implementation, a base station for facilitating device to device
discovery is described. The base station includes a processor and a broadcast module coupled to
the processor. In one implementation, the broadcast module receives a service request from a
service availing device seeking to avail at least one service, wherein the service request indicates
the at least one service. The broadcast module further provides a link message to the service
availing device and at least one service offering device associated with the at least one service,
based on the service request, for initiating device discovery to establish a D2D link for availing
the at least one service. The broadcast module may further generate a service list based on a
registration request, wherein the service list includes service details of one or more services
offered by one or more service offering devices registered with the base station, wherein each of
the one or more services is provided by one or more service offering devices associated with the
service. Thereafter, the broadcast module broadcasts the service list. The base station may further
include a registration module coupled to the processor. The registration module receives the

4

registration request from the service availing device and each of the one or more service offering
devices, wherein the registration request includes at least one of an identity credentials, a service
name, and a service information. Further, the registration module registers the service availing
device and the one or more service offering device based on the identity credentials.
[0007] In accordance with another implementation of the present subject matter, a
computer-readable medium having embodied thereon a computer program for executing a
method of D2D discovery is described. The method includes receiving a service request from a
service availing device seeking to avail at least one service, wherein the service request indicates
the at least one service. The method further comprises providing a link message to the service
availing device and at least one service offering device associated with the at least one service
for initiating device discovery based on the service request.
BRIEF DESCRIPTION OF THE FIGURES
[0008] 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 to reference
like features and components. Some embodiments of system and/or methods in accordance with
embodiments of the present subject matter are now described, by way of example only, and with
reference to the accompanying figures, in which:
[0009] Figure 1 illustrates an exemplary network environment implementation for device
to device (D2D) communication, according to an embodiment of the present subject matter;
[0010] Figure 2 illustrates a method for device to device (D2D) discovery, according to
an embodiment of the present subject matter; and
[0011] Figure 3 illustrates a method for establishing a D2D link, in accordance with an
embodiment of the present subject matter.
DESCRIPTION OF EMBODIMENTS
[0012] With advancement in technology, communication techniques, such as device-
device (D2D) communication have been developed as an alternate means of communication
amongst user devices for reducing network traffic over a conventional wireless communication
network. The D2D communication typically involves communication between two user devices,

5

in proximity to each other, without the use of network elements, such as a base station. For
instance, Wifi Direct and Bluetooth techniques enable two or more user devices, in proximity to
each other, to communicate with each other over a D2D link established between them.
[0013] Establishment of the D2D link is typically preceded with a D2D discovery
mechanism used for discovering a user device for establishing the D2D link. In a conventional
D2D discovery mechanism, a user device continually scans the surrounding environment for
determining presence of one or more user devices offering several services in the surrounding
environment. The user device then ascertains the service being offered by each of the user
devices and subsequently selects a second user device for seeking the services offered by the
second user device. However, continuous scanning of the surrounding environment by the user
device may lead to high consumption of battery power, thereby resulting in limited operational
time and low battery backup for the user device. Further, the scanning capabilities of the user
device may be limited due to the limited transmission range of the user device, thereby limiting
the operational capabilities of the user device. In a conventional method for establishing a D2D
link, a first user device may continually transmit beacon signals in order to discover other
devices in radio frequency (RF) proximity of the first user device. For example, in a mall or a
stadium, a group of friends seeking to establish the D2D link amongst themselves may
continually transmit beacon signals over the wireless network. In such a case, continuous
transmission of such beacon signals may thus lead to increase in the number of channel resources
being utilized resulting in network congestion.
[0014] The present subject matter discloses systems and methods for D2D discovery.
According to an embodiment of the present subject matter, one or more service offering devices
may offer services, such as music broadcast, gaming, printing, content sharing, and video
broadcasting in an environment supporting D2D communication between user devices. In order
to avail any of the aforementioned services using the D2D communication, a user may initially
select the service through a corresponding service availing device. Upon selection of the service,
a base station associated with a network operator of the service availing device may provide the
details of service offering devices offering the selected services to the service availing device.
The service availing device may thus establish a D2D link based on the details. The present
subject matter thus facilitates the D2D discovery. In one implementation, one or more user

6

devices may initially register with the base station associated with their respective network
operators in order to avail or provide the services.
[0015] In said embodiment, the base station may initially broadcast a service list having
details of one or more services offered by the one or more service offering devices such that each
of the one or more services is provided by one or more user devices associated with the service.
In one implementation, the service list may include services which a user device may avail in its
RF proximity. In another implementation, the service list may also include the services provided
by service offering devices that are not in RF proximity of the service availing devices but are
present in the same geographical region as the service availing devices. The user of the service
availing device in such a case may move closer to the service offering devices to come in their
RF proximity for availing the service.
[0016] Upon receiving the broadcast, a user of a service availing device may seek to
avail a service from amongst the one or more services enlisted in the service list. For example,
the user upon receiving the service list including services, such as gaming, music broadcast, and
content sharing, may wish to listen to music and may subsequently select the music broadcast
service from the service list.
[0017] Upon receiving a user input from the user, the service availing device may select
the service which the user seeks to avail. Subsequently, the service availing device may transmit
a service request indicating the selected service to the base station. Upon receiving the service
request, the base station may determine a service offering device from the one or more service
offering devices providing the service. The base station may subsequently provide a link
message to the service availing device and the service offering device for initiating a device
discovery mechanism. In one implementation, the link message may include, identity credentials,
such as an internet protocol (IP) address and a machine address (MAC-id). In another
implementation, the base station may transmit the link message to the service availing device and
more than one service offering devices providing the service.
[0018] Thereafter, the service availing device may initiate a device discovery mechanism
based on the link message and may subsequently establish a D2D link with the service offering
device for availing the service. In another implementation, the service offering device may
initiate the device discovery based on the link message and establish the D2D link with the

7

service availing device. The service offering device may subsequently offer the service to the
service availing device over the D2D link.
[0019] In another embodiment, before receiving the service list, a service availing device
may send a service request to the base station for availing a service which the user may seek to
avail. Upon receiving the service request, the base station may ascertain the availability of the
service based on an internal service record. In a case where the service is available, the base
station may transmit a link message to the service availing device and at least one service
offering device providing the service. The service availing device and the at least one service
offering device may subsequently establish a D2D link in a manner as described above.
[0020] As will be understood from the foregoing description, the services available in a
geographical region or a nearby geographical region of the user device is broadcasted by the base
station, in the form of a service list, the need for continually transmitting the beacon signals for
discovering other user device offering services is averted. Thus, the D2D discovery in
accordance with the present subject matter results in an efficient utilization of spectrum and
channel resources. Further, establishment of the D2D link based on the link message results in
lower battery consumption as the user device is provided with a smaller set of user devices
offering the desired service. Thus, the need for scanning the surrounding environment and
subsequently ascertaining the service provided by each of the user device present in the
proximity is eliminated leading to less battery power consumption. Further, processing of a
limited number of user devices for establishing the D2D link helps in reducing the time involved
in the D2D discovery mechanism. Moreover, the presence of a centralized network entity, such
as the base station helps in monitoring and providing the services across an increased range of
discovery as the base station broadcasts the list of available services to all the user devices. The
user device may thus be provided with a range of choices of services and service offering devices
as compared to the situation where, the user device, when scanning on its own, may be able to
determine the devices and corresponding services in its radio frequency (RF) proximity only.
Thus, the range of discovery over which the services may be discovered is substantially
increased. Further, the deployment of base station for D2D discovery enables intelligent
monitoring of the user devices. For instance, the base station may alert two users connected
through a social networking service, such as a friend application or a social networking website,
when the corresponding user devices are in vicinity of each other.

8

[0021] 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 herein, embody the
principles of the present subject matter and are included within its spirit and scope. Further, all
examples recited herein are principally intended expressly to be only for pedagogical purposes to
aid the reader in understanding the principles of the present 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 thereof.
[0022] The manner in which the systems and the methods for D2D communication shall
be implemented has been explained in details with respect to the Figures 1-3. While aspects of
described systems and methods for D2D communication can be implemented in any number of
different computing systems, transmission environments, and/or configurations, the
embodiments are described in the context of the following exemplary system(s).
[0023] Figure 1 illustrates a network environment 100 for device to device (D2D)
communication. The network environment 100 includes one or more user devices 102-1, 102-2,
102-3, …., and 102-N, hereinafter collectively referred to as the user devices 102 and
individually referred to as the user device 102, through a network 104, according to an
embodiment of the present subject matter.
[0024] The user devices 102 may be defined as User Equipments (UEs) used by users to
communicate with each other. Examples of the user devices 102 include, without limitation,
mobile phones, landline phones, desktop computers, hand-held devices, laptops or other portable
computers, network computers, and the like. Each of the user devices 102 work on a
communication protocol as defined by the communication network to which the user device 102
is coupled. In one implementation, the user devices 102 may communicate with each other for
availing services, such as gaming, music broadcast, location services, printing, content sharing,
and the like in D2D communication mode. The D2D communication involves direct
communication between the user devices 102 without using network resources, such as a base
station 106.

9

[0025] The network 104 may be a wireless network, or a combination of wired and
wireless networks. The network 104 can be a collection of individual networks, interconnected
with each other and functioning as a single large network (e.g., the internet or an intranet).
Examples of such individual networks include, but are not limited to, 3rd Generation Partnership
Project (3GPP), Long Term Evolution (LTE), and the like. Further, depending on the technology,
the network 104 may include various network entities, such as gateways, routers; however, such
details have been omitted for ease of understanding. The network 104 further comprises the base
station 106. In one implementation, the base station 106 enables communication between the
user devices 102 over the network 104.
[0026] According to an embodiment of the present subject matter, one or more user
devices 102 may offer several services, such as gaming, content sharing, music broadcast, video
broadcast, printing, location based services, advertisement messages, and the like in a D2D
communication mode. The D2D communication involves direct communication between two
user devices, in proximity of each other, without using conventional wireless communication
networks and network elements thereof. In said embodiment, a user may seek to avail any of the
services available in the D2D communication mode through a corresponding user device, such as
the user device 102-1. For the sake of clarity, and not as a limitation, in a case where the user
devices 102 may offer any of the aforementioned services, the user devices 102 may be referred
to as the service offering devices 102. Further, where the user may avail any of the
aforementioned services through any of the user devices 102 corresponding to the user, the user
devices 102 may be referred to as the service availing devices 102. In one implementation, the
base station 106 facilitates a D2D discovery mechanism for enabling the service availing device
102 to establish a D2D link with the service offering device 102 to avail the services offered by
the service offering device 102.
[0027] In one implementation, the user device 102 and the base station 104 include
processors 108-1 and 108-2, respectively. The processors 108-1 and 108-2, hereinafter
collectively referred to as the processor 108, may be implemented as one or more
microprocessors, microcomputers, microcontrollers, digital signal processors, central processing
units, state machines, 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.

10

[0028] The functions of the various elements shown in the figure, including any
functional 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.
[0029] Also, the user device 102 and the base station 104 include I/O interface(s) 110-1
and 110-2, respectively. The I/O interfaces 110-1 and 110-2, collectively referred to as I/O
interfaces 110 may include a variety of software and hardware interfaces that allow the user
device 102 and the base station 104 to interact with the network 106, or with each other. Further,
the I/O interfaces 110 may enable the user device 102 and the base station 104 to communicate
with other communication and computing devices, such as web servers and external repositories.
The user device 102 and the base station 104 may further include memory 112-1, and 112-2,
respectively, collectively referred to as memory 112. The memory 112-1 and 112-2 may be
coupled to the processor 108-1, and the processor 108-2, respectively. The memory 112 may
include any 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.).
[0030] The user device 102 and the base station 104 include modules 114-1, 114-2 and
data 116-1, 116-2, respectively, collectively referred to as modules 114 and data 116,
respectively. The modules 114 include routines, programs, objects, components, data structures,
and the like, which perform particular tasks or implement particular abstract data types. The
modules 114 further include modules that supplement applications on the user device 102 and
the base station 104, for example, modules of an operating system.
[0031] Further, the modules 114 can be implemented in hardware, instructions executed
by a processing unit, or by a combination thereof. The processing unit can comprise a computer,
a processor, such as the processor 108, a state machine, a logic array or any other suitable
devices capable of processing instructions. The processing unit can be a general-purpose
processor which executes instructions to cause the general-purpose processor to perform the
required tasks or, the processing unit can be dedicated to perform the required functions.

11

[0032] In another aspect of the present subject matter, the modules 114 may be machine-
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 data 116 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 114.
[0033] In an implementation, the modules 114-1 of the user device 102 include an
interaction module 118, an analysis module 120, and other module(s) 122. In said
implementation, the data 116-1 of the user device 102 includes interaction data 124, analysis data
126, and other data 128. The other module(s) 122 may include programs or coded instructions
that supplement applications and functions, for example, programs in the operating system of the
user device 102. The other data 128 comprise data corresponding to one or more other module(s)
122.
[0034] Similarly, in an implementation, the modules 114-2 of the base station 104
include a registration module 130, a broadcast module 132, and other module(s) 134. In said
implementation, the data 116-2 of the base station 104 includes registration data 136, broadcast
data 138, and other data 140. The other module(s) 134 may include programs or coded
instructions that supplement applications and functions, for example, programs in the operating
system of the base station 104. The other data 140 comprise data corresponding to one or more
other module(s) 134.
[0035] In one implementation, a user may seek to avail at least one service in the D2D
communication mode through a corresponding service availing device 102. For the purpose, the
interaction module 118 may send a registration request to the registration module 130. In one
implementation, the registration request may include identity credentials, such as an internet
protocol (IP) address, a media access control (MAC) address, and device identity.
[0036] Similarly, one or more service offering devices 102 may initially register with a
network operator for offering the services in the D2D communication mode. For the purpose, the
interaction module 118 may send the registration request to the registration module 130. In said

12

implementation, the registration request may include identity credentials of the service offering
devices 102, a service name of the service being offered, and service information. The service
name and the service information may, together or individually, be referred to as service details.
In one example, the service information may include at least one of a type, a quality of service
parameter, and a service discovery range. The service discovery range as used herein indicates a
desired range, of area, over which the service may be discovered and availed by the service
availing devices 102. For example, a service offering device 102-1 may wish to be discovered
across multiple cells and thus may specify the service discovery range accordingly.
[0037] In one implementation, the user device 102 may register both as the service
offering device and the service availing device in case the user of the user device 102 seeks to
avail certain services and offer certain other services.
[0038] Upon receiving the registration request, from the user devices 102, the registration
module 130 may subsequently authenticate and register the service offering devices 102 and the
service availing devices 102 based on identity credentials included in the registration request. In
one implementation, the registration module 130 may register the service availing devices 102
and the service offering devices 102 in separate listings.
[0039] Upon successful registration of each of the service offering devices 102, the
registration module 130 may generate a service list based on the registration request. In one
implementation, the service list may include the service names of the services being offered. In
another implementation, the service list may include the service names and the service
information corresponding to each of the service name included in the service list. For instance,
the service list may include service names like abc, xyz, and pqr and corresponding service
information like music broadcast, gaming, and printing. Thus, the service information may aid
the user in selecting a particular service from the service list. Further, the registration module
130 may maintain a service record for keeping a record of the one or more services being offered
and the corresponding service offering devices 102 associated with each of the service. In one
implementation, the registration module 130 may store the service list and the service record in
the registration data 136.

13

[0040] In one implementation, the service list may include both, the services being
offered in the RF proximity and the services being offered in the nearby geographical region of
the service availing devices.
[0041] Upon generation of service list, the broadcast module 132 may broadcast the
service list to enable the service availing devices 102 to select a service they may wish to avail.
In one implementation, the broadcast module 132 may broadcast the service list periodically,
say, on hourly basis. In another implementation, the broadcast module 132 may broadcast the
service list at predetermined time durations of a day. In yet another implementation, the
broadcast module 132 may broadcast the service list either upon detecting presence of a new user
device 102 in the vicinity or upon each updation of the service list. For the purpose, the
broadcast module may obtain the service list stored in the registration data 136 and may
subsequently transmit the service list.
[0042] In one implementation, the interaction module 118 of the service availing devices,
say a service availing device 102-1, in vicinity of the base station 106 may receive and store the
service list in the interaction data 124. Upon receiving the service list, the user may seek to avail
a particular service, in the RF proximity or the nearby geographical region, included in the
service list and may provide a user input for selecting the service name. Based on the user input,
the analysis module 120 may generate a service request including request details, such as the
service name and the service type which the user may wish to seek. The analysis module 120
may subsequently transmit the service request to the broadcast module 132.
[0043] Upon receiving the service request, the broadcast module 132 may store the
service request in the broadcast data 138. Based on the service requested, the broadcast module
132 may ascertain at least one service offering device, say a service offering device 102-2 from
the corresponding offering devices 102 associated with the service. The broadcast module 132
may obtain the service record stored in the registration data 136 and may subsequently select the
service offering device 102-2 based on the service information associated with the service
offering device 102-2. In another implementation, the broadcast module 132 may select more
than one service offering devices 102 from the one or more service offering devices 102.
Subsequently, the broadcast module may generate a link message. In one implementation, the
link message may include identity credentials of the service availing device 102-1 and the

14

identity credentials and the service information of the service offering device 102-2. In another
implementation, where the broadcast module 132 may select more than one service offering
device 102, the link message may include the identity credentials and the service information
corresponding to each of the selected service offering device 102.
[0044] Subsequently, the broadcast module 132 may transmit the link message to the
service availing device 102-1 and the service offering device 102-2 for establishing the D2D
link. Thereafter, the service availing device 102-1 may establish the D2D link with the at least
one service offering device 102 based on the identity credentials of the service offering device
102-2 included in the link message. As mentioned previously, the service availing device 102-1
may seek to avail a service in the nearby geographical region. In such a case, the service availing
device 102-1 may move in the RF proximity of the service offering device and then subsequently
establish the D2D link with the service offering device 102-2.
[0045] In another implementation, the broadcast module 132 may transmit the link
message to the service availing device 102-1 and each of the selected service offering devices
102. Upon receiving the link message, in one case, any of the selected service offering devices
102 may initiate the D2D link establishment based on the identity credentials of the service
availing device 102-1. In another case, the service availing device 102-1 may select the at least
one service offering device 102 from the selected service offering devices 102 based on the
service information included in the link message and may subsequently establish the D2D link
with the at least one service offering device 102.
[0046] In another embodiment, upon successful registration with the network operator
and before receiving the service list, the user may wish to seek a particular service, for example,
a printing service. For the purpose, the interaction module 118 may transmit the service request
to the broadcast module 132. In one implementation, the service request may include the service
information corresponding to the service the user may wish to seek. For instance, in the previous
example of printing service, the service request may include the type of service as printing
service. In another implementation, the service request may include the service name. For
example in a case where the user may seek to play a particular game, the service request may
include the name of the game.

15

[0047] Upon receiving the service request, the broadcast module 132 may scan the
service list stored in the broadcast data 138 and ascertain the availability of the service. Further,
in an implementation, the broadcast module 132 may scan the broadcast data to determine
whether a new service has been registered which may not have been included in the service list.
In a case, where the broadcast module 132 ascertains that the service is available, the broadcast
module 132 may subsequently provide the link message to the service availing device 102-1 in a
manner as described above. Further, in the case where the service has not been updated in the
service list, the broadcast module 132 may update the service list. The service availing device
102-1 may then establish a D2D link with a service offering device, say service offering device
102-2 to avail the printing service.
[0048] In another embodiment, where the D2D link needs to be established in a haste, the
base station 106 may reserve one or more channel resources from the pool of channels for such
quick D2D link establishment. For instance, two users travelling in different vehicles, in close
proximity of each other, may seek to establish a D2D link for sharing content amongst
themselves Subsequently, upon receiving the registration request from the service availing
device 102-1 and the service offering device 102-2 seeking to establish the D2D link in said
embodiment, the base station 104 may transmit channel information corresponding to the
reserved channel resources to the service availing device 102-1 and the service offering device
102-2. The service availing device 102-1 and the service offering device 102-2 may subsequently
establish the D2D link over the reserved channel resources.
[0049] In yet another embodiment, the service offering device 102-2 may provide relay
services that the service availing device 102-1 may wish to seek. For example, the service
offering device 102-2 may wish to act as a transmitter, such as a wireless router, for transmitting
data packets received from the base station 106 to the service availing device 102-1. In such a
case, upon successful registration, the broadcast module 132 may transmit a link message to the
service availing device 102-1 and the service offering device 102-2. In such a case, the link
message may include the identity credentials of both the service availing device 102-1 and the
service offering device 102-2. Upon receiving the link message, either of the service availing
device 102-1 and the service offering device 102-2 may subsequently initiate the D2D link
establishment based on the link message.

16

[0050] Figure 2 illustrates a method 200 for device to device (D2D) discovery, according
to an embodiment of the present subject matter. Figure 3 illustrates a method 300 for establishing
a D2D link, according to an embodiment of the present subject matter.
[0051] The order in which the methods 200 and 300 are described is not intended to be
construed as a limitation, and any number of the described method blocks can be combined in
any order to implement methods 200 and 300, or an alternative method. Additionally, individual
blocks may be deleted from the methods 200 and 300 without departing from the spirit and scope
of the subject matter described herein. Furthermore, the methods 200 and 300 may be
implemented in any suitable hardware, machine readable instructions, firmware, or combination
thereof.
[0052] A person skilled in the art will readily recognize that steps of the methods 200 and
300 can be performed by programmed computers. Herein, some examples are also intended to
cover program storage devices and non-transitory computer readable medium, for example,
digital data storage media, which are machine or computer readable and encode machine-
executable or computer-executable instructions, where said instructions perform some or all of
the steps of the described methods 200 and 300. 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.
[0053] With reference to Figure 2, at block 202, a service list including details of one or
more services is broadcasted. In one implementation, one or more service offering devices may
offer several services, such as gaming, printing, music broadcast, location based services, and
video broadcast in a device to device (D2D) communication mode. Further, a service availing
device may seek to avail any of the services. For the purpose, both the service availing device
and the service offering device may register with the network operator. Thereafter, the service
list may be generated based on the services being offered by the service offering devices. The
service list may include one or more services, such that each of the one or more services is
provided by the one or more service offering devices associated with the service. In one
implementation, the service list may be broadcasted by a base station of the network operator.
For example, the base station 104 may broadcast the service list after a predetermined interval.

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[0054] At block 204, a service request from a service availing device is received. In one
implementation, a user may seek to avail a service enlisted in the service list. For the purpose,
the user may send a service request through a corresponding service availing device. The service
request may indicate the service which the user may wish to seek. In one implementation, the
base station 104 may receive the service request.
[0055] At block 206, a link message is provided based on the service request. In one
implementation, upon receiving the service request, at least one service offering device, from
amongst the one or more service offering device, associated with the service included in the
service request is ascertained. Thereafter, a link message is provided to the service availing
device and the at least one service offering device. The link message may include identity
credentials of the service availing device and the at least one service offering device.
Subsequently, either of the service availing device and the at least one service offering device
may initiate the device discovery mechanism based on the link message for establishing a D2D
link amongst themselves. In another implementation, identity credentials of one or more service
offering devices, offering the service, may be provided in the link message along with the
identity credentials of the service availing device. In such a case, the D2D link may be
established between the service availing device and any one of the service offering device.
[0056] As described previously, figure 3 illustrates a method for establishing a D2D link.
With reference to figure 3, at block 302, a registration is performed with a base station for
availing services in device to device communication mode. In one implementation, a registration
request may be sent for registering a service availing device in order to avail services in the D2D
communication mode. The registration request may include identity credentials, such as an IP
address, a MAC address, and device identity. Upon receiving the registration request, the device
may be registered. In one implementation, the base station 104 may receive a registration request
from the service availing device 102-1.
[0057] At block 304, a service list is obtained from the base station. Upon successful
registration of the service availing device, a service list is obtained. In one example, the service
list may include service details of one or more services, where each of the one or more service is
provided by one or more service offering devices associated with the service. In one example,
the service availing device 102-1 may obtain the service list broadcasted by the base station 106.

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[0058] At block 306, a service request is provided. In one example, a user may select a
service from the service list. Subsequently, a service request may be sent to the base station. The
service request may indicate the selected service. In one example, the service availing device
102-1 may send the service request to the base station 106.
[0059] At block 308, a link message based on the service request is received. Upon
receiving the service request, a link message including identity credentials of at least one service
offering device associated with the service and the identity credentials of the service availing
device is received by the service availing device.
[0060] At block 310, a D2D link is established. Based on the identity credentials
included in the link message, the D2D link is established between the service availing device and
the at least one service offering device. In one implementation, the service availing device may
initiate the process of establishment of the D2D link. In another implementation, the at least one
service offering device from amongst the one or more service offering devices may initiate the
D2D link establishment upon receiving the link message.
[0061] Although embodiments for methods and systems for D2D communication have
been described in a language specific to structural features and/or methods, it is to be understood
that the invention is not necessarily limited to the specific features or methods described. Rather,
the specific features and methods are disclosed as exemplary embodiments for D2D
communication.


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I/We claim:
1. A method for device to device (D2D) discovery, the method comprising:
receiving, by a base station (106), a service request from a service availing device
(102) seeking to avail at least one service, wherein the service request indicates the at
least one service; and
providing, by the base station (106), a link message to the service availing device
(102) and at least one service offering device (102) associated with the at least one
service, based on the service request, for initiating device discovery to establish a D2D
link for availing the at least one service.
2. The method as claimed in claim 1, wherein the method further comprises:
receiving, by the base station (106), a registration request from each of the one or
more service offering devices (102), wherein the registration request includes at least one
of an identity credentials, service name, and service information, and wherein the service
information includes at least one of a name, a type, a quality of service, and a service
discovery range; and
registering, by the base station (106), each of the one or more service offering devices
(102) based on the corresponding identity credentials included in the registration request.
3. The method as claimed in any of the preceding claims, wherein the method further
comprises broadcasting, by the base station (106), a service list including service details
of one or more services offered by the one ore more service offering devices (102)
registered with the base station (106), wherein each of the one or more services is
provided by one or more service offering devices (102) associated with the service.
4. The method as claimed in claim 3, wherein the method further comprises generating the
service list based on the registration request.
5. The method as claimed in any of the preceding claims, wherein the service details include
at least one of the service name and the service information.
6. The method as claimed in claim 1, wherein the method further comprises ascertaining, by
the base station (106), availability of the at least one service using a service record stored
in the base station (106), based on the service request.

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7. A method for device to device (D2D) discovery, the method comprises:
providing, by a service availing device (102), a service request for availing at least
one service to a base station (106), wherein the service request indicates the at least one
service;
receiving, by the service availing device (102), a link message for initiating device
discovery with at least one service offering device (102) associated with the at least one
service, based on the service request, to establish a D2D link for availing the at least one
service.
8. The method as claimed in claim 7, wherein the method further comprises obtaining, by
the service availing device (102), a service list including service details of one or more
services from a base station (106), wherein each of the one or more services is provided
by one or more service offering devices (102) associated with the service.
9. The method as claimed in claim 7, wherein the method further comprises establishing, by
the service availing device (102), the D2D link with the at least one service offering
device (102) associated with the at least one service.
10. The method as claimed in claim 7, wherein the providing further comprises selecting the
at least one service based on a user input.
11. The method as claimed in claim 7, wherein the method further comprises sending, by the
service availing device (102), a registration request for registering with the base station
(106), wherein the registration request includes at least one of an identity credentials,
service name, and service information, and wherein the service information includes at
least one of a name, a type, a quality of service, and a service discovery range.
12. A base station (106) comprising:
a processor (108-2);
an broadcast module (132) coupled to the processor (108-2) to,
receive a service request from a service availing device (102) seeking to avail at
least one service, wherein the service request indicates the at least one service; and
provide a link message to the service availing device (102) and at least one
service offering device (102) associated with the at least one service, based on the
service request, for initiating device discovery to establish a D2D link for availing the
at least one service.

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13. The base station (106) as claimed in claim 12, wherein the base station (106) further
comprises a registration module (130) coupled to the processor (108-2) to,
receive a registration request from the service availing device (102) and each of the
one or more service offering devices (102), wherein the registration request includes at
least one of an identity credentials, a service name, and a service information; and
register the service availing device (102) and the one or more service offering device
based on the identity credentials.
14. The base station (106) as claimed in claim 12, wherein the broadcast module (132)
further,
generates a service list based on the registration request, wherein the service list
includes service details of one or more services offered by one or more service offereing
devices registered with the base station (106), wherein each of the one or more services is
provided by one or more service offering devices (102) associated with the service; and
broadcasts the service list.
15. The base station (106) as claimed in claim 12, wherein the broadcast module (132)
further ascertaining, by the base station (106), availability of the at least one service
based on a service record stored in the base station (106).
16. A computer-readable medium having embodied thereon a computer program for device
to device (D2D) discovery, the method comprising:
receiving a service request from a service availing device seeking to avail at least one
service, wherein the service request indicates the at least one service; and
providing a link message to the service availing device and at least one service
offering device associated with the at least one service, based on the service request, for
initiating device discovery to establish a D2D link for availing the at least one service.