The present invention relates to the allocation and configuration of Device-to-Device
(D2D) channels for use by mobile radio communication devices such as User Equipments (UE)
operating within a cellular communications network environment. In particular the invention
relates to a method of configuring D2D channels within such an environment, a method of
operating a UE to achieve such configuration, and related UE devices and computer
programming products providing for such configuration.
Background Art
[0002]
The concept of proximity based services (ProSe) within a cellular communications
network environment has been identified as a mechanism for improving communication capacity
and quality for service for UEs operating within such an environment while improving network
capability by UEs off-loading. D2D communication is intended to allow for appropriate quality
of service communication, between UEs operating within a cellular network environment and
employing some network resources but not requiring communication through the network.
Summary of Invention
Technical Problem
[0003]
Recent developments and discussions within the 3rd Generation Partnership Product
(3GPP) community have identified requirements for D2D functionality and which include in
particular the support of unicast communications between UEs, for example UE pairs, in D2D
communication or the support of broadcast or groupcast communications between UEs, for
example from some UE towards other UEs.
[0004]
However, current proposals remain limited and, while some potential features have been
identified and discussed, proposals for various aspects such as the configuration of physical
channel resources remain limited and as yet undeveloped.
[0005]
Such known discussions have centred on potential core system assumptions. That is,
while potential agreement has been reached that a cell's uplink spectrum should be used for D2D
communication, there are currently only proposals that the allocation of radio resources for D2D
communication be centralised within the cell base station (eNB) or Cluster Head of the cluster of
terminal devices. Also a further proposal is that the assignment of resources for D2D
communication be performed with reference to the legacy Physical Downlink Control Channel
(PDCCH) of the cellular network. Yet further it has also been discussed that multiplexing
between cellular uplink and D2D transmissions, that is either data and/or control-related
information, within a common subframe can be employed and that a specific Physical Control
Channel be introduced for D2D communication (P2CCH) to carry control information directly
between the UEs engaged in D2D communication, i.e. the so-called peer UEs of a D2D pair.
Such a proposed P2CCH D2D channel can support functionality such as a Hybrid Automatic
Repeat Request (HARQ) mechanism for the exchange of Ack/Nack feedback between the peer
UEs, or for the estimate of radio conditions between the peer UEs, such as the exchange of
Channel Quality Indicator (CQI) information.
[0006]
Further, in addition to the newly proposed control channel, a new Physical Shared
Channel is illustrated for D2D communication (P2SCH) for the transport of data, such as user
data or user signalling, directly between the peer UEs.
[0007]
In relation to such proposals, there are different suggestions for resource
allocation/configuration in relation to D2D communication scenarios within cellular
communication networks. However current suggestions exhibit inefficiencies and tend to have an
undesired impact on the cellular environment and in particular in relation to the legacy Physical
Uplink Control Channel (PUCCH) and base station (eNB) functionality of a cell.
[0008]
One such known system is disclosed in WO2012/159270 and which comprises a
mechanism for allocating communication resources of a cellular communication network to D2D
communication but which is disadvantageous ly limited and simply focuses on legacy radio
resources, such as the frequency-band and resource-pool to be employed for D2D
communication.
[0009]
The present invention seeks to provide for a method of configuring channel resources to
convey control information for D2D communication within a cellular communications network
environment, and to related mobile communication terminal devices and computer program
products, having advantages over known such method related devices and computer programme
products.
Solution to Problem
[0010]
According to one aspect of the present invention there is provided a method of
configuring a physical channel, such as a physical control channel, for device-to-device
communication between mobile terminal devices within a cellular communications network
environment and comprising a step of locating a device-to-device control channel within a
cellular uplink signalling spectrum, and applying a frequency offset parameter to determine
separation of the device-to-device control channel from a cellular uplink control channel.
[0011]
In particular, the step of locating the device-to-device control channel can be determined
within one of the said mobile terminal devices.
[0012]
According to another aspect of the present invention there is provided a method of
operating a mobile terminal device for device-to-device communication within a cellular
network environment and including, within the device, the step of locating a device-to device
control channel within a cellular uplink signalling spectrum, and applying a frequency offset
parameter to determine separation of the device-to-device control channel from a cellular uplink
control channel.
[0013]
The present invention, in all its various aspects, proves advantageous when considering
possible impact on cellular connectivity within the network environment, and the legacy PUCCH
in particular. It proves possible in particular to maintain downlink cellular capacity, and avoid
radio interference between the legacy PUCCH and the configured P2CCH, through setting the
said frequency offset to establish the appropriate distance/separation between the two control
channels.
[0014]
Further, the invention will exert only limited impact on an eNB scheduler through the
effective separation of the D2D and cellular controls, i.e. through the provision of separate
scheduling.
[0015]
Also, only limited added functionality and/or complexity need arise at the mobile
terminal device, due to adoption of legacy cellular-channel calculation algorithms as described
further herein.
[0016]
Yet further, it can advantageously prove possible to maintain single carrier
characteristics for SC-FDMA transmission in all channels and thereby avoiding PUSCH
fractioning.
[0017]
Of course the offset value can be established in the context of Resource Blocks.
[0018]
The methods can also include the step of identifying the bandwidth of the
device-to-device control channel.
[0019]
Preferably, the methods include a step of determining the frequency offset by reference
to cellular network uplink/downlink signalling.
[0020]
Advantageously, the step of determining the frequency offset parameter can include an
adaption of an algorithm employed for determining physical uplink control channel
characteristics within the cellular network environment.
[0021]
Further, the terminal device can receive data identifying the location of the
device-to-device control channel by way of Radio Resource Control SIB messaging.
[0022]
If required, the methods can also include the step of identifying common configuration
parameter values between terminal devices. Advantageously the common configuration
parameter values can be computed by means of a message exchange, such as a random channel
access procedure between two mobile terminal devices.
[0023]
Also, the common configuration parameter values can be determined on the basis of
RRC SIB signalling in which neighbouring cell parameters are broadcast.
[0024]
The methods can thus be provided, for configuration of a mobile terminal device when
served by a different cell of that of another mobile terminal device within a Radio Access
Network.
[0025]
The methods can also be provided relation to a mobile terminal device outside RAN
coverage of that of another mobile terminal device including the configuration of physical
control channel for the device-to-device communication by way of a previously camped-on cell,
or by way of a pre-set value in the USIM.
[0026]
If required, the method can include the step of employing a discovery beacon for
transport of device-to-device channel location parameters between the mobile terminals, and/or
include the step of employing initial access signalling within a legacy random access procedure
for the exchange of initial access messaging.
[0027]
Also, the method can include the step of employing a X2 message/parameter for
network-node to network-node communications for building neighbouring cell physical channel
parameters.
[0028]
According to a further aspect of the present invention there is provided a cellular
communications network mobile terminal device arranged for device-to-device communication
with a further mobile terminal device and arranged for locating a device-to-device control
channel within a cellular uplink signalling spectrum, and applying a frequency offset parameter
to determine separation of the device-to-device control channel from a cellular uplink control
channel.
[0029]
Such a device can be arranged to operate in accordance with any one or more of the
method features noted above.
[0030]
According to a yet further aspect of the present invention there is provided a computer
program product for a computer device, comprising software code portions for performing the
steps of any of the above method features when said product is run on the computer device.
[0031]
Also, the computer program product can comprise a computer-readable medium on
which said software code portions are stored.
[0032]
Likewise, the computer program product of the invention can be directly loadable into
the internal memory of the computer device and/or transmittable via a network by means of at
least one of upload, download and push procedures.
Brief Description of Drawings
[0033]
The invention is now described further, by way of example only, with reference to the
accompanying drawings in which:
[Fig- 1]
Fig. 1 is a schematic diagram illustrating D2D communication between peer UEs within
a cellular network environment in which the invention can be adapted;
[Fig. 2]
Fig. 2 is a schematic representation of successive subframes illustrating configuration
according to one aspect of the present invention;
[Fig- 3]
Fig. 3 is a schematic representation of successive subframes illustrating configuration
according to another aspect of the present invention;
[Fig. 4]
Fig. 4 is a schematic diagram of a subframe exhibiting configuration according to the
embodiment of Fig. 3;
[Fig. 5]
Fig. 5 is a signalling diagram illustrating transmission sequence for legacy network
transmissions and D2D communication;
[Fig- 6]
Fig. 6 is a schematic representation of subframe configuration according to a further
feature of the present invention;
[Fig. 7]
Fig. 7 is a schematic representation of a mobile radio communications terminal device
arranged to operate in accordance with an embodiment of the present invention; and
[Fig. 8]
Fig. 8 is a conceptual diagram of "Figure 5.4.3-1 : Mapping to physical resource blocks
for PUCCH" disclosed in section 5.4 of 3GPP TS 36.211.
Description of Embodiments
[0034]
Referring now to Fig. 1 there is provided a schematic representation of terminal devices
within a cellular communication network environment 10 and comprising a base station device
in the form of an eNB 12, a first mobile radio communications terminal device such as a first UE
14 and a second such mobile radio communications device such as a second UE 16.
[0035]
As illustrated by the signalling to be discussed further below, the first and second UEs
14, 16 are arranged to exchange cellular uplink and downlink signalling with the eNB 12 by way
of uplink and downlink control and shared channels in accordance with cellular communication
functionality. In addition, and in accordance with the field of the present invention, the UEs 14,
16, are also arranged for D2D communication with advantageously reduced/limited impact on
the cellular network resources. Schematically illustrate therefore are uplink control/data
channels PUCCH/PUSCH 18 for uplink control/data traffic from the first 14 and second 16 UEs
to the eNB 12. There are also schematic illustrated downlink control/data channels
PDCCH/PDSCH 20 for receipt at each of the UEs 14, 16 of data from the network, i.e. eNB 12.
[0036]
As noted, the UEs 14, 16 are also arranged to form a UE pair for mutual D2D
communication and, in this context, and on the basis of the concept of the present invention,
D2D control information 22, such as HARQ feedback signalling, can be exchanged between the
two UEs 14, 16 by way of a physical control channel, and D2D data can be exchanged 24
between the two UEs 14, 16 by way of a physical shared data channel. Such control and data
channels are specific to the D2D communications and within the present application are
identified as P2CCH and P2SCH respectively.
[0037]
While a single cell common Radio Access Network (RAN) is illustrated with reference
to Fig. 1, it should be appreciated that the present invention can be employed by a D2D UE pair
according to various network configuration scenarios. That is, in addition to adoption in relation
to a UE pair such as operating under Frequency Division Duplex (FDD) or Time Division
Duplex (TDD) RAN coverage in an intra-cell scenario such as that in Fig. 1, where both UEs 14,
16 are served by a single cell, the invention also finds use in relation to an inter-cell coverage
scenario in which the UEs are served by different cells/eNBs.
[0038]
Yet further, the invention can also be adopted in relation to UEs operating outside RAN
coverage as discussed further herein but still allowing for the exchange of D2D data between a
UE pair by way of unicast communication.
[0039]
It should also be appreciated from the above summary of the present invention and the
following discussions, that the invention is advantageous in providing for management of the
coexistence of legacy uplink channels PUCCH, PUSCH, and D2D channels P2CCH, P2SCH
within the uplink band spectrum consisting of PUCCH and PUSCH. As a particular advantage,
the invention allows for both UE devices within a D2D UEs pair to identify the location of radio
resources in time and/or frequency, at which transmission/reception should be attempted in the
uplink band so as to access the D2D control information related to that D2D UEs pair link. Also,
the invention allows for the cellular network node device, such as the eNB, to discriminate
between transmissions on the legacy uplink channels from those on the D2D channels and, in
general terms, allows for the reduction in potential interference between the channels and impact
of one on the other.
[0040]
With regard to Fig. 2 and Fig. 3, there are illustrated schematic representations of the
structure of adjacent subframes and related Resource Blocks providing for adoption of the
P2CCH and P2SCH channels within the context of the present invention for D2D
communication and particularly for coexistence with the legacy uplink control and shared data
channels, PUCCH, PUSCH.
[0041]
Turning first to Fig. 2, the Resource Blocks considered in the frequency domain and
within the adjacent subframes 26, 28, within their frequency spectrum, are divided between
PUCCH channel element 30, D2D P2CCH channel element 32 for D2D control information
exchanges between the D2D UEs pair, a PUSCH channel 34 for cellular network data uplink
exchanges, and a D2D P2SCH channel 36 for D2D data exchanges between that pair.
[0042]
Fig. 2 illustrates the coexistence between the uplink and D2D channels on a Frequency
Division Multiplex basis such that Resource Blocks of the adjacent subsequent subframe 28
exhibit the same characteristics as the preceding subframe 26.
[0043]
Turning now to Fig. 3, there is provided similar structural diagram of adjacent
subframes 38, 40 within a series and again, by reference to the frequency spectrum, being
divided between uplink control channel PUCCH portions 42, D2D control channel P2CCH
portions 44 and 46, in this particular example, Uplink and/or D2D shared channels
PUSCH/P2SCH for data exchanges. Again, the structure of the subsequent subframe 40
mirrors that of the initial subframe 38 so as to represent a full FDM scenario within the uplink
channel spectrum between the uplink and D2D control PUCCH/P2CCH and data
PUSCH/P2SCH channels.
[0044]
While it would be possible to employ time division multiplexing for the coexistence of
the uplink and D2D control and data channels, such an arrangement may exhibit a more
restricted operation as regards legacy PUCCH bandwidth availability, and increased latency, for
the respective control channels, or can further inhibit the flexibility of the eNB in dividing the
uplink spectrum bandwidth between the D2D uplink transmissions and thus adapting to network
load.
[0045]
One particular example of an arrangement for arriving at an FDM subframe structure
such as illustrated in particular with reference to Fig. 3, is now described with reference to Fig. 4.
[0046]
Fig. 4 illustrates in particular the adoption of new system parameters serving to define
the location of the P2CCH channel for the D2D communication.
[0047]
The location of this D2D control channel P2CCH is advantageously defined by way of
two parameters, referenced to the frequency spectrum employed by uplink Resource Blocks and
first comprising a frequency offset parameter by means of which the D2D control channel
P2CCH is offset relative to the legacy uplink control channel PUCCH, and also the actual D2D
control channel P2CCH bandwidth. Such parameters are shown in Fig. 4 which illustrates in
the context of one subframe, a Resource Block 38 encompassing a frequency spectrum (not
shown) in a vertical direction as illustrated in Fig. 3 and, as previously noted, employing uplink
control channel portions 42, D2D control channel portions 44 and shared general portion 46 for
uplink and/or D2D data.
[0048]
As illustrated by the arrows P2CCH_Off associated with each of the uplink control
channel regions 42, the D2D control channel 44 is offset, in accordance with the frequency
division multiplexing requirements, relative to the uplink control channel 42. The second
parameter comprises the bandwidth of the D2D control channel 44 which, in Fig. 4 is illustrated
by double-headed arrow P2CCH_BW.
[0049]
Thus, the D2D parameters P2CCH_Off and P2CCH_BW serve to define the location,
through frequency offset, and bandwidth, of each of the D2D control channels 44. The
remainder of the Resource Block spectrum then not employed by the UE respective uplink and
D2D control channels 42, 44 is available for the shared communication channel 46. Of course
the alternative of Fig. 2 with respective FDM D2D and uplink shared data channels can be
similarly employed.
[0050]
As noted previously, the parameters exhibited by the present invention can also be
employed in accordance with different network radio coverage scenarios.
[0051]
In particular, for the radio coverage scenario in which the D2D UEs pair are within
network coverage, the parameters tend to be unique to each cell and the values are provided to
camped-on UEs through the radio resource control SIB signalling. That is, for intra-cell
coverage where both of the D2D UEs pair are within the same cell, both UEs can compute the
location of the Resource Blocks, and the number of allocated Resource Blocks to be used, by
running an algorithm which can be such as that employed for identification of the Resource
Blocks in the PUCCH channel, and adding the aforementioned P2CCH_Off value to the
outcome.
[0052]
For a radio coverage scenario in which the D2D UEs pair are in inter-cell coverage, the
D2D UEs pair are likely to have different values for the offset and bandwidth parameters duplet
and so a common duplet should be identified. As outlined further below, such common duplet
can be defined by reference to the intersection of the two P2CCH zones, and the P2CCH_BW
parameters can be advantageously employed for computing such a common duplet.
[0053]
Further details of determining the parameters employed within the invention and the
common duplet are outlined further below. However, with regard to an out-of-coverage network
scenario, the D2D UEs pair may also exhibit different values for the duplet, which can arise from
pre-set values, or previously received values when under network coverage, and a similar
procedure to that adopted in relation to the inter-cell coverage to determine a common duplet as
discussed further below can be employed.
[0054]
A further feature of the invention relates to a procedure for a recipient UE in a D2D UEs
pair to position/assign an appropriate P2CHH channel for the transfer of control information
such as D2D HARQ feedback signalling.
[0055]
Various forms of algorithm are possible for such location/assignment although one
particularly advantageous embodiment is based upon algorithms employed for the assignment of,
for example, control channel radio resources of the legacy PUCCH channel based upon
information concerning the location of assigned information in the legacy downlink control
channel PDCCH.
[0056]
Such legacy algorithm and the associated assignment/location is known from legacy
LTE systems such as disclosed in 3GPP Technical Specification TS 36.21 1 in section 5.4 the full
content of which is incorporated herein by reference, and but for completeness, the principal
sections are outlined below as follows:
[0057]
5.4.3 Mapping to physical resources
The block of complex-valued symbols z(i) shall be multiplied with the amplitude
scaling factor PUCCH in order to conform to the transmit power PUCCH specified in Section
5.1.2. 1 in [4], and mapped in sequence starting with z(0) to resource elements. PUCCH uses one
resource block in each of the two slots in a subframe. Within the physical resource block used for
transmission, the mapping of z t) to resource elements (k, ) not used for transmission of reference
signals shall be in increasing order of first k, then / and finally the slot number, starting with the
first slot in the subframe.
The physical resource blocks to be used for transmission of PUCCH in slot n are given
by
where the variable m depends on the PUCCH format. For formats 1, 1a and l b
PUCCH
N shift
3 normal cyclic prefix
2 extended cyclic prefix
and for formats 2, 2a and 2b
m LnPUCCH / Nsc J
Mapping of modulation symbols for the physical uplink control channel is illustrated in
Figure 5.4.3-1.
In case of simultaneous transmission of sounding reference signal and PUCCH format 1,
1a or 1b, one SC-FDMA symbol on PUCCH shall punctured.
Fig. 8 is a conceptual diagram of "Figure 5.4.3-1 : Mapping to physical resource blocks
for PUCCH" disclosed in section 5.4 of GPP TS 36.211
[0058]
For the D2D communication arising in relation to the present invention, the
assigned/location of the required P2CCH is derived from the use of such known algorithm
wherein both UEs in a D2D pair receive the assignment for the D2D transmission for data, and
the UE receiving the data is arranged to run the aforementioned legacy algorithm which provides
a "virtual" Resource Blocks location in the physical uplink control channel. The receiving UE
can then add the aforementioned offset P2CCH_Off value to the outcome of the algorithm within
the frequency spectrum as disclosed in relation to Fig. 4 so as to move to the "effective"
computed Resources Blocks in the P2CCH zone.
[0059]
An example of the transmission sequence arising between an eNB and a D2D UE pair,
for both the legacy signalling, and for D2D control channel configuration according to an
embodiment of the present invention is now discussed further with reference to Fig. 5.
[0060]
Fig. 5 represents a timing diagram within a frequency spectrum (vertical access but not
specifically illustrated) encompassing both a downlink carrier and uplink carrier and also
illustrating the UE Resource Blocks appearing within a series of subframes 50, 52, 54 relating, as
noted, to both the legacy signalling and the D2D control and data channel P2CCH, P2SCH
signalling within the legacy uplink spectrum.
[0061]
Within subframe 50, and within the downlink carrier spectrum, there is provided a
physical downlink channel 56 within which a eNB (not shown) assigns a Resource Block 58 for
downlink traffic and within which the eNB also assigns a Resource Block 64 for D2D
communication between first and second UEs of a D2D pair. The subframe. 50, also includes a
Resource Block 62 representing a downlink shared channel by means of which the eNB sends
data 64 related to the RB assignment 58 to the UE.
[0062]
With regard to the legacy elements of the signalling, a downlink HARQ resource
location algorithm is applied so as to identify a portion within PUCCH channel 66 employed by
a first UE while sending HARQ feedback 68 on downlink reception at the first UE. Within the
next subframe 52 illustrated, a physical control channel 70 is calculated on the basis of the
legacy algorithm as discussed above. However, with regard to the Resource Block 64 assigned
by the eNB for D2D communication, the first UE sends D2D data 74 to the second UE within
the D2D pair. Referring to the Resource Block structure within the subframe 54, there is again
provided a physical uplink control channel 76, and a physical control channel 78, for D2D
communication and associated shared data channel 80. Referring again to the assignment by
the eNB of the Resource Block 64 D2D communication, the adapted D2D HARQ resource
location algorithm is applied to provide for the required HARQ signalling 82 on D2D reception.
[0063]
Although, within the context of the control channel signalling, reference is made above
to the HARQ mechanism, it should be appreciated that the subject matter of the present
invention could equally be implemented in relation to any other required control information,
such as for example CQI information.
[0064]
As also discussed above, the present invention is not limited solely to D2D UE pairs
operating D2D communication within the same cell, and inter-cell, or indeed out-of-coverage,
adoption of the concept of the present invention can also be achieved.
[0065]
An appropriate interworking rule is proposed to cover embodiments relating to inter-cell,
or out-of-coverage, D2D communication for a UE pair. In both instances, the two UEs in the
D2D pair do not exhibit the same duplet, i.e. offset value and/or control channel bandwidth,
since they are camping on different cells. However, to allow for the D2D communication, both
UEs can be arranged to compute the intersection/overlap of their respective P2CCH zones to
identify a common duplet and such feature is described further with reference to Fig. 6.
[0066]
Fig. 6 illustrates Resource Block structures for first 84, and second 86 UEs within a
D2D UE pair, and both of which include functionality according to a feature of the present
invention so as to provide for a virtual common Resource Block configuration 88 as illustrated.
[0067]
The basic structure illustrated within the sub-frames for each of the two UEs 84, 86 is
based upon a feature of an embodiment of the present invention illustrated with reference to Fig.
4.As such, they provide for a FDM scheme within the frequency spectrum of the legacy uplink
channel, and wherein the Resource Block structure includes uplink control channel zones, offset
derived D2D control channel zones, and shared data channels for uplink and/or D2D
communication as required.
[0068]
However, as illustrated, in view of the differences arising from the two UEs 84, 86
camping on different cells, there is quite likely to be a lack of coincidence between the respective
boundaries of the respective D2D control channels P2CCH. That is, UE 84 exhibits an upper
boundary for its D2D control channel equivalent to "offset 1 + bandwidth 1"; and UE 86 exhibits
an upper boundary for its D2D control channel P2CCH of "offset 2 + bandwidth 2" where
respective "offset 1", 94 and "offset 2", 96 are determined relative to the legacy uplink control
channels PUCCH as discussed above.
[0069]
In order to arrive at the common configuration structure 88, the upper boundary is
determined as the minimum of the two values 90, 92, whereas the lower boundary is determined
as the maximum of the two offset values 94, 96 and as illustrated by the dotted lines in Fig. 6.
[0070]
Applying such combined limits leads to a common P2CCH control channel 98 as
illustrated and so allows for adoption of the mechanism of the present invention for inter-cell and
out-of-coverage scenarios.
[0071]
Turning now to Fig. 7, there is provided a schematic illustration of a mobile terminal
device offering communication over cellular network and comprising for example, a UE 100 of a
D2D UE pair.
[0072]
The UE 00 includes standard functionality such as a transmission/reception interface
comprising an antenna 102 and transmission/reception circuitry 104 in addition to memory
functionality 106, processor functionality 108 and a user interface 110.
[0073]
In accordance with the present invention, the processor functionality 108 includes
means for achieving the required channel configuration according to the present invention so as
to enable the D2D communication exchanges exhibiting the advantages presented by the
invention. That is, the processor functionality 108 can be arranged to determine and/or apply
parameter values arising in accordance with the present invention and serving to identify the
frequency offset values and bandwidth values as discussed.
[0074]
In particular, the processor functionality 108 can be arranged to determine the
aforementioned frequency offset value by reference to legacy algorithms determining initial
physical Resource Blocks for control information transportation and applying the required
frequency offset to the results obtained therefrom. In this manner, such D2D UE 100 can
determine the location of the required physical Resource Blocks for the transport of D2D control
information, although it should be appreciated here that other mathematical operation, i.e. sum,
subtraction etc. can be employed.
[0075]
As will also be appreciated, various mechanisms exist for supporting the signalling
exchange for the D2D control channel system parameters according to the present invention, and
which can relate to the particular network terminal and/or node devices involved in the signalling
exchange.
[0076]
For example, while for exchanges between a terminal node such as eNB and a mobile
terminal such as a UE, RRC System Information Broadcast (SIB) messages/parameters can be
employed, an eNB can broadcast its own cell parameter set. Also the eNB can broadcast a
parameter set of neighbouring cells if required and which can prove useful for out-of-coverage
embodiments as discussed above.
[0077]
For communication between the UEs, it can of course prove necessary to supply data for
computing the common configuration features such as discussed in relation to Fig. 6. Here,
transport options include use of a discovery beacon to convey P2CCH parameters and/or the use
of initial access signalling in legacy random access procedures such as the D2D UE pair
exchanging initial access messaging including their specific P2CCH parameters. Other
alternative option is that specific P2CCH parameter set data can be employed and also, if
required, a camped-on cell identity can prove advantageous in allowing retrieval of a parameter
set in the neighbouring cell P2CCH parameters within the SIB.
[0078]
For network terminal node, e.g. eNB to eNB, signalling, use can be made of X2
interface messages/parameters which can also prove useful for building neighbouring cell
P2CCH messages/parameters as required.
[0079]
As will therefore be appreciated from the above, the present invention provides for an
advantageous scheme that can be readily embodied within a channel configuration procedure,
terminal device operation procedure, and related computer program product, to advantageously
allow for D2D capable UEs to determine which part of the legacy uplink band can be
advantageously dynamically used for D2D, and P2CCH purposes in particular.
[0080]
It should be appreciated that in particular there can be provided system parameters to
define the location of a proposed P2CCH channel, such parameters comprising:
P2CCH Frequency Offset employed to compute the frequency shifting from legacy
PUCCH and hence get the P2CCH lower boundary if the offset is added to the PUCCH lower
boundary; and
P2CCH bandwidth employed to get the P2CCH upper boundary.
[0081]
A particular algorithm function can be employed for location of physical resource
blocks for D2D physical control channel, and such proposed algorithm can be based on legacy
LTE algorithm found in Technical Specification 36.21 1 as noted above. After running the
legacy algorithm to find initial physical resource blocks to transport control information, P2CCH
Frequency Offset can be used to allow the D2D UEs to find physical resource blocks to transport
D2D control information. Of course it should be appreciated that other mathematical operation
could be used such as sum, subtraction, etc.
[0082]
Further exemplary detail of the manner and transfer of physical control information can
be as suggested by 3GPP Technical Specification 36.213, the content of which is again
incorporated herein by reference.
[0083]
Suggested signalling options for P2CCH system parameters can comprise the use of
RRC signalling to provide the proposed system parameters: SIB or dedicated RRC messages,
and such parameters could also be pre-configured in the UEs: pre-set by the network operator in
USIM or predefined by the 3GPP specifications.
[0084]
The advantageous adoption of the above-mentioned interworking computation rule for
non matching cell-derived parameter can focus upon the intersection of the P2CCH zones
computed from the P2CCH Frequency Offset and P2CCH bandwidth parameters could be
chosen to find the common duplet used by UEs which have been provided different P2CCH
configuration. Of course, any other rule using the P2CCH Frequency Offset and P2CCH
bandwidth parameters could also be used such as union rule, sum rule etc.
[0085]
The signalling for such interworking can allow for the exchange of the proposed system
parameters between eNB using X2 interface. Further, the proposed system parameters could also
be exchanged between UEs using discovery beacons or legacy radio access signalling between
D2D UEs.
[0086]
The efficient dynamic operation and assignment of D2D channel resources according to
the present invention is achieved in a particular advantageous manner. In particular, there is little
if any limiting impact on legacy PUCCH, and hence it remains possible to maintain downlink
cellular capacity.
[0087]
Further, radio interference between legacy PUCCH and P2CCH can readily be avoided
by setting P2CCH_Off to create the right separation/distance between the two channels. There is
also an advantageously limited impact on eNB scheduler through the persistent availability of
cellular control signalling whose scheduling can be separated from D2D scheduling.
[0088]
There is also only limited added complexity from the UE point of view, particularly
when considering reuse of the legacy algorithm.
[0089]
Finally it remains possible to maintain Single Carrier characteristics for SC-FDMA
transmission in all channels and thus minimizing as much as possible PUSCH fractioning.
[0090]
This application is based upon and claims the benefit of priority from United Kingdom
patent application No. 1401772.7, filed on January 31, 2014, the disclosure of which is
incorporated herein in its entirety by reference.
[0091]
The whole or part of the embodiments disclosed above can be described as, but not
limited to the following supplementary notes.
[Supplementary note 1]
A method of configuring a physical channel for device-to-device communication
between mobile terminal devices within a cellular communications network environment and
comprising a step of locating a device-to-device control channel within a cellular uplink
signalling spectrum, and applying a frequency offset parameter to determine separation of the
device-to-device control channel from a cellular uplink control channel.
[Supplementary note 2]
A method as claimed in Supplementary note 1, and including the step of, identifying a
bandwidth parameter of the device-to-device control channel.
[Supplementary note 3
A method as claimed in Supplementary note 1 or 2, and including the step of
determining the frequency offset by reference to cellular network control channel.
[Supplementary note 4]
Amethod as claimed in Supplementary note 3, wherein the step of determining the
device-to-device physical radio resource blocks from the frequency offset parameter by
including an adaption of an algorithm employed for determining physical uplink control channel
characteristics within the cellular network environment.
[Supplementary note 5]
A method as claimed in any one or more of Supplementary notes 1-4, and location of
the device-to-device control channel is determined within one of the said mobile terminal
devices.
[Supplementary note 6]
A method as claimed in any one or more of Supplementary notes 1-5, wherein said
parameters identifying the location of the device-to-device control channel are delivered to the
terminal devices by way of Radio Resource Control cell broadcast so called as SIB or terminal
dedicated SIB messaging.
[Supplementary note 7]
Amethod as claimed in any one or more of Supplementary notes 1-5, and including the
step of identifying common configuration parameters values between the said terminal devices.
[Supplementary note 8]
A method as claimed in Supplementary note 7, wherein the common configuration
parameters values are computed by means of messages exchanges between two mobile terminal
devices.
[Supplementary note 9]
A method as claimed in Supplementary note 7, wherein the common configuration
parameter values are determined on the basis of RRC SIB signalling in which neighbouring cell
parameters are broadcast.
[Supplementary note 10]
A method as claimed in any one or more of Supplementary notes 7-9, and providing
configuration of the mobile terminal devices when served by different cells within a Radio
Access Network.
[Supplementary note 1 ]
A method as claimed in any one or more of Supplementary notes 1-6, and for mobile
terminal devices outside RAN coverage, and including the configuration of a physical control
channel for the device-to-device communication by way of a previously camped-on cell, or by
way of a pre-set value in the USIM.
[Supplementary note 12]
A method as claimed in any one or more of Supplementary notes 1-11, and including the
step of employing a discovery beacon for transport of device-to-device channel location
parameters between the mobile terminals.
[Supplementary note 13]
A method as claimed in any one or more of Supplementary notes 1-11, and including the
step of employing initial access signalling within a legacy random access procedure for the
exchange of device-to-device channel location parameters.
[Supplementary note 14]
A method as claimed in any one or more of Supplementary notes 1-13, and including
step of employing an X2 message/parameter for network node to network node communications
for providing serving cell physical channel parameters.
[Supplementary note 15]
A method of operating a mobile terminal device for device-to-device communication
within a cellular network environment and including, within the device, the step of locating a
device-to device control channel within a cellular uplink spectrum, and applying a frequency
offset parameter to determine separation of the device-to-device control channel from a cellular
uplink control channel.
[Supplementary note 16]
A method as claimed in Supplementary note 15, and also including the step of
identifying the bandwidth of the device-to-device control channel.
[Supplementary note 17]
A method as claimed in Supplementary note 15 or 16, and including the step of
determining the frequency offset by reference to cellular network control channel.
[Supplementary note 18]
A method as claimed in any one or more of Supplementary notes 15-17, wherein the
step of determining device-to-device physical radio resource blocks from the frequency offset
parameter comprises including an adaption of an algorithm employed for determining physical
uplink control channel characteristics within the cellular network environment.
[Supplementary note 19]
A method as claimed in any one or more of Supplementary notes 15-18, wherein the
terminal device receives said parameters identifying the location of the device-to-device control
channel by way of Radio Resource Control SIB messaging.
[Supplementary note 20]
A method as claimed in any one or more of Supplementary notes 15-19, and including
the step of identifying common configuration parameter values between terminal devices.
[Supplementary note 21]
A method as claimed in Supplementary note 20, wherein the common configuration
parameter values are computed by means of a message exchange, such as a random channel
access procedure between two mobile terminal devices.
[Supplementary note 22]
A method as claimed in Supplementary note 20, wherein the common configuration
parameter values are determined on the basis of RRC SIB signalling in which neighbouring cell
parameters are broadcast.
[Supplementary note 23]
A method as claimed in any one or more of Supplementary notes 20-22, for
configuration of a mobile terminal device when served by a different cell of that of another
mobile terminal device within a Radio Access Network.
[Supplementary note 24]
A method as claimed in any one or more of Supplementary notes 15-20, in relation to a
mobile terminal device outside RAN coverage of that of another mobile terminal device
including the configuration of physical control channel for the device-to-device communication
by way of a previously camped-on cell, or by way of a pre-set value in the USIM.
[Supplementary note 25]
A cellular communications network mobile terminal device arranged for
device-to-device communication with a further mobile terminal device and arranged for locating
a device-to-device control channel within a cellular uplink spectrum, and applying a frequency
offset parameter to determine separation of the device-to-device control channel from a cellular
uplink control channel.
[Supplementary note 26]
A terminal device as claimed in Supplementary note 25, and arranged to identify a
bandwidth of the device-to-device control channel.
[Supplementary note 27]
A terminal device as claimed in Supplementary note 25 or 26, and arranged to determine
the frequency offset by reference to cellular network control channel.
[Supplementary note 28]
A terminal device as claimed in any one or more of Supplementary notes 25-27, and
arranged to determine device-to-device physical resource blocks from the frequency offset
parameter by way of algorithm employed for determining physical uplink control channel within
the cellular network environment.
[Supplementary note 29]
A terminal device as claimed in any one or more of Supplementary notes 25-28, and
arranged to receive said parameters identifying the location of the device-to-device control
channel by way of Radio Resource Control SIB or terminal dedicated messaging.
[Supplementary note 30]
A terminal device as claimed in any one or more of Supplementary notes 25-29, and
arranged for identifying configuration parameters common with another terminal device.
[Supplementary note 3 ]
A computer program product for a computer device, comprising software code portions
for performing the steps of any one of Supplementary notes 1-24 when said product is run on the
computer device.
[Supplementary note 32]
A computer program product according to Supplementary note 31, wherein the
computer program product comprises a computer-readable medium on which said software code
portions are stored.
[Supplementary note 33]
A computer program product according to Supplementary note 31 or 32, wherein the
computer program product is directly loadable into the internal memory of the computer device
and/or transmittable via a network by means of at least one of upload, download and push
procedures.
Reference Signs List
[0092]
10 cellular communication network environment
12 eNB 12
14 first UE
16 second UE
100 UE
102 antenna
104 transmission/reception circuitry
106 memory functionality
108 processor functionality
110 user interface

CLAIMS
[Claim 1]
A mobile terminal device which supports device-to-device communication with a
further mobile terminal device comprising:
reception circuit configured to receive control information which includes a first offset
from a resource of a first uplink control channel; and
a processor configured to determine a resource for a first device-to-device control
channel based on the first offset.
[Claim 2]
The mobile terminal device as claimed in claim 1, wherein the control information
further includes information regarding a bandwidth of the first device-to-device control channel.
[Claim 3]
The mobile terminal device as claimed in claim 2, wherein the processor configured to
determine the resource for the first device-to-device control channel based on the information
regarding the bandwidth of the first device-to-device control channel.
[Claim 4]
The mobile terminal device as claimed in claim 2 or 3, wherein the information
regarding the bandwidth of the first device-to-device control channel comprises the number of
Resource Blocks.
[Claim 5]
The mobile terminal device as claimed in any one of claims from 1 to 4, wherein control
information which includes a second offset from a resource of a second uplink control channel.
[Claim 6]
The mobile terminal device as claimed in claim 5, wherein the processor configured to
determine the resource for a second device-to-device control channel based on the second offset.
The mobile terminal device as claimed in any one of claims from 1 to 6, wherein the
control information is transmitted by a Radio Resource Control message.
[Claim 8]
A method of operating a mobile terminal device which supports device-to-device
communication with a further mobile terminal device, the method comprising:
receiving control information which includes a first offset from a resource of a first
uplink control channel; and
determining a resource for a first device-to-device control channel based on the first
offset.
[Claim 9]
The method as claimed in claim 8, wherein the control information further includes
information regarding a bandwidth of the first device-to-device control channel.
[Claim 10]
The method as claimed in claim 9, wherein the step of determining the resource for the
first device-to-device control channel is a step of determining the resource for the first
device-to-device control channel based on the information regarding the bandwidth of the first
device-to-device control channel.
[Claim 11]
The method as claimed in claim 9 or 10, wherein the information regarding the
bandwidth of the first device-to-device control channel comprises the number of Resource
Blocks.
[Claim 12]
The method as claimed in any one of claims from 8 to 11, wherein control information
which includes a second offset from a resource of a second uplink control channel.
[Claim 13]
The method as claimed in claim 12, further comprising: determining the resource for a
second device-to-device control channel based on the second offset.
[Claim 14]
The method as claimed in any one of claims from 8 to 13, wherein the control
information is transmitted by a Radio Resource Control message.
[Claim 15]
A computer program for causing a computer to perform the step of any one of claims
from 8 to 14.