The present disclosure relates to communications devices configured to communicate with other communications devices via a device-to-device (D2D) wireless access interface and methods of operating communications devices to communicate via a D2D wireless access interface.
The present disclosure claims the Paris convention priority from EP19203127.6 filed 14 Oct. 2019 the contents of which are incorporated herein by reference.
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Third and fourth generation mobile telecommunication systems, such as those based on the 3GPP defined UMTS and Long Term Evolution (LTE) architecture, are able to support more sophisticated services than simple voice and messaging services offered by previous generations of mobile telecommunication systems. For example, with the improved radio interface and enhanced data rates provided by LTE systems, a user is able to enjoy high data rate applications such as mobile video streaming and mobile video conferencing that would previously only have been available via a fixed line data connection. The demand to deploy such networks is therefore strong and the coverage area of these networks, i.e. geographic locations where access to the networks is possible, may be expected to increase ever more rapidly.
One aspect of LTE is a provision for communications devices to communicate directly with each other rather than communicating via a wireless communications network. Device-to-device communications or D2D communications has been specified for LTE for devices when both in coverage and out of coverage of a wireless communications network. To communicate devices transmit and receive signals via a D2D wireless access interface.
Future wireless communications networks will be expected to routinely and efficiently support communications with a wider range of devices associated with a wider range of data traffic profiles and types than current systems are optimised to support. For example it is expected future wireless communications networks will be expected to efficiently support D2D communications, whilst utilising features of such networks. There is therefore a desire for future wireless communications networks, for example those which may be referred to as 5G or new radio (NR) system/new radio access technology (RAT) systems [1], as well as future iterations/releases of existing systems, to support D2D communications as efficiently as possible.
The present disclosure can help address or mitigate at least some of the issues discussed above.
Embodiments of the present technique can provide a method of operating a communications device configured for D2D, communications. The method comprises receiving on a control channel of a D2D wireless access interface an indication of communications parameters from another communications device for that other communications device to transmit signals representing data to the communications device via a shared channel of the D2D wireless access interface, the D2D wireless access interface providing physical resources for the control channel and the physical resources of the shared channel. The communications device may therefore be thought of as a first or receiving communications device and the other communications device may be thought of as a second or transmitting communications device. The method further comprises receiving the signals representing the data via the physical resources of the shared channel of the D2D wireless access interface based on the received communications parameters. The physical resources of the shared channel of the D2D wireless access interface are formed from a default bandwidth part and a non-default bandwidth part of the D2D wireless access interface between the communications device and the other communications device. Furthermore the default bandwidth part has a narrower bandwidth of the D2D wireless access interface than the non-default bandwidth part.
By configuring communications devices with a default bandwidth part and a non-default bandwidth part of a D2D wireless access interface, the devices can switch between communicating via the default bandwidth part and the non-default bandwidth part. Since the default bandwidth part has a lower bandwidth than the non-default bandwidth part, the communications devices can be arranged for example to reduce their power consumption when communicating data with a lower bandwidth requirement, because power consumption of the devices is proportional to a bandwidth of the D2D wireless access interface being used.
In some examples the default bandwidth part and the non-default bandwidth part may be configured by a wireless communications network, the default bandwidth part being one which is monitored and used by the communications devices, whereas the non-default bandwidth part may be used when there is a requirement for an increased bandwidth.
Respective aspects and features of the present disclosure are defined in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the present technology. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.
A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein like reference numerals designate identical or corresponding parts throughout the several views, and wherein:
To provide a better understanding of example embodiments the following sections provide an explanation of background techniques including an LTE network, a 5G or New Radio network and device-to-device communications.
Long Term Evolution Advanced Radio Access Technology (4G)
The network 100 includes a plurality of base stations 101 connected to a core network 102. Each base station provides a coverage area 103 (i.e. a cell) within which data can be communicated to and from terminal devices 104. Data is transmitted from base stations 101 to terminal devices 104 within their respective coverage areas 103 via a radio downlink (DL). Data is transmitted from terminal devices 104 to the base stations 101 via a radio uplink (UL). The core network 102 routes data to and from the terminal devices 104 via the respective base stations 101 and provides functions such as authentication, mobility management, charging and so on. Terminal devices may also be referred to as mobile stations, user equipment (UE), user terminal, mobile radio, communications device, and so forth. Base stations, which are an example of network infrastructure equipment/network access node, may also be referred to as transceiver stations/nodeBs/e-nodeBs/eNBs/g-nodeBs/gNBs and so forth. In this regard different terminology is often associated with different generations of wireless telecommunications systems for elements providing broadly comparable functionality. However, certain embodiments of the disclosure may be equally implemented in different generations of wireless telecommunications systems, and for simplicity certain terminology may be used regardless of the underlying network architecture. That is to say, the use of a specific term in relation to certain example implementations is not intended to indicate these implementations are limited to a certain generation of network that may be most associated with that particular terminology.
New Radio Access Technology (5G)
In terms of broad top-level functionality, the core network component 210 of the new RAT communications network represented in
A communications device or UE 260 is represented in
In the example of
It will further be appreciated that
Thus example embodiments of the disclosure as discussed herein may be implemented in wireless telecommunication systems/networks according to various different architectures, such as the example architectures shown in
Device-to-Device Communications
Device-to-Device (D2D) communications is an aspect of mobile communications which has been established for devices to communicate directly with each other rather than via a wireless communications network. That is to say that radio signals representing data are transmitted via a wireless interface by one device and received by another to communicate that data, rather than the signals being transmitted to radio infrastructure equipment of a wireless communication network, which are then detected and decoded by the infrastructure equipment to recover that data and communicated on to a destination device.
D2D communications can take different forms which are illustrated in
Another example of D2D communications is also shown in
Here D2D communications of the form of sidelink 314 are referred to as in-coverage communications, D2D communications of the form of sidelink 340 are referred to as partial coverage communications, and D2D communications of the form of sidelinks 330, 332, 334 are referred to as out-of-coverage communications.
According to 3GPP standards such as LTE, whilst downlink and uplink communications are specified for transmissions from an infrastructure equipment such as a gNB to a UE and from a UE to a gNB respectively, sidelink communications are specified to realise UE-to-UE (device-to-device (D2D)) communication, especially for sidelink discovery, sidelink communication and vehicle to everything (V2X) sidelink communication between UEs. The LTE sidelink has the following characteristics [3GPP specification, TS36.300, v15.7.0]:
Currently, for 5G or New Radio (NR) standardisation, a sidelink has been specified in Release-16 for V2X communication, with the LTE sidelink being a starting point for the NR sidelink NR sidelink can be enhanced with a power saving mechanism for sidelink which would be a useful feature especially for D2D (device-to-device) communications between devices having limited battery power.
Bandwidth Parts and Power Consumption
UE battery life is an aspect which will influence the adoption of 5G devices and/or services. UE power saving is aimed at providing UE power efficiency for 5G NR, so that the power saving is comparable with or better than that of LTE. Release-15 UE power saving schemes can provide UE power saving in NR operation.
One of the UE power saving schemes is BWP (bandwidth part) adaptation. A BWP is a part of a carrier bandwidth providing a number of contiguous resource blocks (RBs) which can be grouped to form a bandwidth part (BWP) in NR. Multiple BWPs can exist within a carrier bandwidth, where in Release-15 up to four BWPs can be configured per UE semi-statically. However only one BWP is activated per UE at a given time.
A UE's power consumption depends on the bandwidth of the BWP and other configuration parameters of the bandwidth part, for example the cross-slot scheduling parameters applied to the BWP. That is, the narrower the bandwidth, the lower power consumption. To reduce the power consumption at the UE, Bandwidth Adaptation (BA) is employed to receive or transmit data as required by the UE. When the UE has a large amount of data to receive and or to transmit, a wide pipe of bandwidth is activated while in case there is only a small amount of data for transmission/reception (i.e. low activity or idle), a narrower BWP is activated. It has been proposed that before activation, a UE may be configured in advance using RRC signalling with a number of BWPs (up to four) within a carrier bandwidth. An example is shown in
Example embodiments can provide a method of operating a UE for D2D communications in which a first receiving UE receives via a control channel or PSCCH of a D2D wireless access interface an indication of communications parameters, such as a bandwidth allocation from a second UE for the first UE to transmit signals representing data to the first UE via a shared channel or PSSCH of the D2D wireless access interface, the D2D wireless access interface providing physical resources for the PSCCH and the physical resources of the PSSCH. The method further comprises receiving the signals representing the data via the physical resources of the PSSCH of the D2D wireless access interface based on the received communications parameters. The physical resources of the PSCCH and/or the PSSCH of the D2D wireless access interface are formed from a default bandwidth part which is pre-established (known) between the UE and the other UE and a non-default bandwidth part which is dynamically configured between the first UE and the second UE. Furthermore the default bandwidth part having a narrower bandwidth of the D2D wireless access interface than the non-default bandwidth part, so that when using the default bandwidth part the UEs can save power.
Bandwidth part (BWP) adaptation is one technique which can be used by a UE to save power. For sidelink power saving, BWP adaptation can be used to save power, as has been specified for NR downlink and uplink communications. However current proposals for the sidelink for NR only provide for one BWP to be configured and configuration of multiple BWPs is not allowed. Furthermore physical resources need to be aligned between a receiver and a transmitter. In other words, the transmitter has to know which BWP is activated for the receiver.
According to example embodiments a UE supporting multiple BWP configurations can be scheduled on the default BWP unless the transmitting UE knows that the receiving UE is monitoring resources other than the default BWP. To be able to receive PSCCH from other transmitting UEs, the receiving UE in some examples always monitors at least the default BWP and in other examples the receiving UE monitors the default BWP as much as possible.
A default BWP can be configured by a wireless access network through radio resource control, RRC, signalling or can be pre-specified as a bandwidth part which exists between a group of UEs before there is a requirement for data to be transmitted between devices. Other attributes include:
A non-default BWP may also be configured by the wireless communications network and can be provided generally for a UE to transmit when a higher bandwidth is required. Other attributes include:
As will be appreciated from the above explanation both a default and a non-default BWPs are pre-configured by RRC signalling. DCI/SCI signalling may then then used to tell a UE which BWP to use, using the known attributes that were pre-configured by RRC.
A more detailed illustration of UEs operating in accordance with example embodiments is illustrated in
As shown in
The controller circuitry 490 of the UEs 420, 422, 424 is configured to control the transmitter circuitry 496 and the receiver circuitry 492 and may comprise processor circuitry which may in turn comprise various sub-units/sub-circuits for providing functionality as explained further herein. These sub-units may be implemented as discrete hardware elements or as appropriately configured functions of the processor circuitry. Thus the controller 490 may comprise circuitry which is suitably configured/programmed to provide the desired functionality using conventional programming/configuration techniques for equipment in wireless telecommunications systems. Likewise, the transmitter 496 and the receiver 492 may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter 496, receiver 492 and controller 490 are schematically shown in
The controllers 490 may be configured to carry out instructions which are stored on a computer readable medium, such as a non-volatile memory. The processing steps described herein may be carried out by, for example, a microprocessor in conjunction with a random access memory, operating according to instructions stored on a computer readable medium.
BWP switching can be UE-specifically performed. For downlink/uplink communications, since a wireless network through the gNB for NR controls access to radio communications resources for the UE, the gNB knows which BWP is activated for the UE. However, for sidelink, a transmitting UE (Tx UE) can control part of the resource allocation for a receiving UE (Rx UE). In addition, multiple Tx UEs can be assumed from a Rx UE perspective. Therefore if a Tx UE indicates BWP switching to an Rx UE, another Tx UE will not know which BWP is activated for the Rx UE.
As shown in
According to one example embodiment, the D2D wireless access interface is configured with a default bandwidth part, BWP, which is within and always inside a non-default BWP in the frequency domain That is to say that, a resource configuration of the D2D wireless access interface is restricted so that the non-default BWP is overlapped with the whole default BWP. In other words, a UE does not expect to be configured with a non-default BWP that is not overlapping with the default BWP. Typically, only one BWP is active, which may be either a default BWP or a non-default BWP. In some examples, multiple non-default BWPs can be configured, but only one BWP is active. Even when the non-default BWP is active, a UE needs to monitor a control channel of the PSCCH within the default BWP.
Example embodiments are arranged to provide a D2D control channel via which UEs may transmit control signals to other UEs using the D2D wireless access interface. According to some example embodiments of the D2D control channel (PSCCH), physical resources for PSCCH monitoring which are common among default BWP and non-default BWP may be configured. For example, CORESETs are common among default and non-default BWP by virtue of there being common Radio Resource Control, RRC, signalling that configures the default and non-default BWPs. Here the CORESET (control resource set) constitutes physical resources for PSCCH monitoring.
In other example embodiments, physical resources for PSCCH monitoring are separately configured for each BWP, but physical resources for PSCCH monitoring on the non-default BWP is restricted within default BWP. For example, although RRC signalling details for each BWP are separate, both BWPs are configured such that the physical resources monitored for PSCCH for either BWP lie in the default BWP.
One example embodiment is illustrated in
From time t1, a UE monitors PSCCH 610 on BWP A. A narrowband PSSCH can be transmitted on BWP A using self-BWP scheduling. When a wideband PSSCH is transmitted to the UE, the UE changes the received BWP to BWP B under the control of the PSCCH 610. SCI (sidelink control information) in PSCCH includes a BWP indicator which indicates the BWP scheduling the PSSCH. After the UE receives PSSCH on BWP B, the UE goes back to monitoring BWP A. For example, the return to monitoring BWP A can be controlled by expiry of an inactivity timer, where the inactivity timer can be configured.
The UE can reduce power consumption by using narrower BWP 600 reception from t1 to t2 and from t5 to the next time that BWP switching occurs.
Here, the time from t2 to t3 and from t4 to t5 is the time gap required for BWP switching.
For an example in which the default BWP is outside the non-default BWP in the frequency domain, including the case where it is partially overlapping, and only one BWP is active (i.e. BWP switching is performed) then the PSCCH may be transmitted on only the default BWP. This example is illustrated in
There are different example techniques for scheduling the different BWP. For example these can be explicitly indicated using a BWP indicator. This can be provided for example in a Sidelink Control Information (SCI) message which can explicitly indicate the scheduled BWP. In another example an implicit indication can be used, for example each non-default BWP can be associated with cast-type (unicast, groupcast, multicast) for D2D communications, priority for D2D data etc. If such an association is configured, the scheduled BWP can be determined by cast-type or priority etc indicated by the SCI message.
If a transmitting UE knows the active non-default BWP for a receiving UE, for example if the transmitting UE is the scheduling UE for a receiving UE using cross-BWP scheduling, then the transmitting UE can transmit further PSCCH/PSSCH for the Rx UE on the scheduled non-default BWP.
In some examples another UE such as the third UE 424 of
If the Rx UE feedbacks a PSFCH (Physical Sidelink Feedback Channel) corresponding to the scheduling PSCCH/PSSCH and other Tx UEs detect the PSFCH, the other Tx UEs can also transmit further PSCCH/PSSCH for the Rx UE on the scheduled non-default BWP. When the receiving UE reports feedback signalling to a transmitting UE using PSFCH, it includes information on the actual characteristics of the receiving UE's BWP monitoring status. For example, the receiving UE can include within the PSFCH one or more of the following pieces of information regarding the status of the receiving UE:
After PSSCH reception is completed on the non-default BWP, the UE can switch to the default BWP. The switching can be done either right after the reception, or a given time after the reception, where the given time is fixed or predetermined, configured by RRC signalling, or indicated by the SCI scheduling the PSSCH. The feedback signal can be transmitted via a PSFCH transmission which can include a HARQ feedback for the PSSCH. In one example the PSFCH can be transmitted on the default BWP. In another example the PSFCH can be transmitted on the scheduled non-default BWP.
According to another example embodiment shown in
Other example embodiments can be provided based on the three embodiments described above with further adaptations. For example transmit and/or receive parameters can be changed based on BWP switching for power saving. For example:
Though embodiments of the present technique have been described largely by way of the example communications system shown in
According to the above examples a UEs forming a group of D2D UEs may be configured to communicate via one or both of a default BWP or a non-default BWP.
S1: A group of UEs exchange signaling information with a wireless communications network, such as RRC signaling which configures each of the UEs of the group to communicate using a D2D wireless access interface. The UEs of the group are configured with a default BWP and a non-default BWP which may have a greater bandwidth of the D2D wireless access interface than the default BWP.
S2: The UEs of the group then monitor a control channel of the default BWP at least for control information which may provide an indication of resources of the shared channel (PSSCH) from which one of the UEs of the group may transmit data. Whilst the control information will always be transmitted on the PSCCH of the default BWP, in some example the physical resources of the PSSCH (shared channel) for transmitting the data may be on the default BWP or non-default BWP or both. The control information may also be transmitted on the PSCCH (control channel) of the non-default BWP.
S3: One of the UEs of the group (UE2) then transmits to another of the UEs of the group (UE1) an indication of communications parameters provided included as least a part of control information on the PSCCH of the default BWP. The communications parameters include an indication of physical resources of a shared channel (PSSCH) on which the other UE, UE1, should receive data.
S4: The other UE (UE1) configures its receiver to receive the data on the PSSCH, which may be part of the non-default BWP or the default BWP, which are switched by the UEs on demand in accordance with a bandwidth requirement for communicating the data.
Those skilled in the art would further appreciate that such infrastructure equipment and/or communications devices as herein defined may be further defined in accordance with the various arrangements and embodiments discussed in the preceding paragraphs. It would be further appreciated by those skilled in the art that such infrastructure equipment and communications devices as herein defined and described may form part of communications systems other than those defined by the present disclosure.
The following numbered paragraphs provide further example aspects and features of the present technique:
Paragraph 1. A method of operating a communications device configured for device-to-device, D2D, communications, the method comprising
Paragraph 2. The method of paragraph 1, wherein the default bandwidth part is configured to be within a frequency range of the non-default bandwidth part, and the receiving the signals representing the data comprises receiving the signals from one of the default bandwidth part or the non-default bandwidth part, only one of which is active at a given time.
Paragraph 3. The method of paragraph 2, wherein the receiving the indication of communications parameters physical resources of the control channel of the D2D wireless access interface comprises
Paragraph 4. The method of paragraph 3, wherein physical resources of the control channel of the D2D wireless access interface are common among the default bandwidth part and the non-default bandwidth part.
Paragraph 5. The method of paragraph 2, wherein the control channel is provided on the default bandwidth part and the non-default bandwidth part, the method comprising
Paragraph 6. The method of paragraph 1, wherein the default bandwidth part is configured to be at least partially outside a frequency range of the non-default bandwidth part.
Paragraph 7. The method of paragraph 6, wherein the receiving the signals representing the data comprises
Paragraph 8. The method of paragraph 7, wherein physical resources of the control channel of the D2D wireless access interface are formed within the default bandwidth part and not the non-default bandwidth part, and the receiving on the control channel of a D2D wireless access interface the indication of communications parameters from the other communications device comprises
Paragraph 9. The method of paragraph 7, wherein physical resources of the control channel of the D2D wireless access interface are provided on both the default bandwidth part and the non-default bandwidth part, and the receiving on the control channel of a D2D wireless access interface the indication of communications parameters from the other communications device comprises
Paragraph 10. A method of operating a communications device configured for device-to-device, D2D, communications, the method comprising
Paragraph 11. The method of paragraph 10, wherein the first indication of the communications parameters is detected on the control channel of the non-default bandwidth part and the transmitting the second indication of the second communications parameters includes transmitting the second indication on the physical resources of the non-default bandwidth part.
Paragraph 12. The method of paragraph 10 or 11, wherein the first indication of communications parameters includes information of characteristics of a whether the second communications device is monitoring the control channel of the default bandwidth part or the non-default bandwidth part.
Paragraph 13. The method of paragraph 10, 11 or 12, wherein the transmitting the second indication of communications parameters to the second communications device comprises
Paragraph 14. The method of paragraph 13, wherein the feedback signal includes an indication of when the second communications device will be monitoring the control channel of the default bandwidth part or the non-default bandwidth part.
Paragraph 15. The method of paragraph 13 or 14, wherein the feedback signal includes an indication of physical resources of the control channel of the default bandwidth part or the non-default bandwidth part which will be monitored by the second communications device.
Paragraph 16. The method of paragraph 1, wherein the receiving the signals representing the data comprises
Paragraph 17. The method of paragraph 1, wherein the communications parameters comprise first communications parameters for configuring the communications device to receive signals from the default bandwidth part and second communications parameters for configuring the communications device to receive signals from the non-default bandwidth part.
Paragraph 18. The method of paragraph 17, wherein the first communications parameters are different to the second communications parameters.
Paragraph 19. The method of paragraph 17 or 18, wherein the first communications parameters include a maximum number of Multiple Input Multiple Output, MIMO, layers for receiving signals via the physical resources of the control channel or the shared channel of the default bandwidth part, and the second communications parameters include a maximum number of Multiple Input Multiple Output, MIMO, layers for receiving signals via the physical resources of the control channel or the shared channel of the non-default bandwidth part.
Paragraph 20. The method of any of paragraphs 1 to 18, wherein the default bandwidth part and the non-default bandwidth part are configured by a wireless communications network, the default bandwidth part having a narrower bandwidth than the non-default bandwidth part.
Paragraph 21. A communications device configured for device-to-device, D2D, communications, the communications device comprising
Paragraph 22. The communications device of paragraph 21, wherein the receiver circuitry is configured to receive signals transmitted by an infrastructure equipment of a wireless communications network, the signals being transmitted via a wireless access interface provided by the wireless communications network, and the controller circuitry is configured to control the receiver circuitry
Paragraph 23. A communications device configured for device-to-device, D2D, communications, the communications device comprising
Paragraph 24. The communications device of paragraph 23, wherein the receiver circuitry is configured to receive signals transmitted by an infrastructure equipment of a wireless communications network, the signals being transmitted via a wireless access interface provided by the wireless communications network, and the controller circuitry is configured to control the receiver circuitry
Paragraph 25. A computer program providing computer executable code, which when executed by a processor causes the processor to perform the method of any of paragraphs 1 to 20.
In so far as embodiments of the disclosure have been described as being implemented, at least in part, by software-controlled data processing apparatus, it will be appreciated that a non-transitory machine-readable medium carrying such software, such as an optical disk, a magnetic disk, semiconductor memory or the like, is also considered to represent an embodiment of the present disclosure.
It will be appreciated that the above description for clarity has described embodiments with reference to different functional units, circuitry and/or processors. However, it will be apparent that any suitable distribution of functionality between different functional units, circuitry and/or processors may be used without detracting from the embodiments.
Described embodiments may be implemented in any suitable form including hardware, software, firmware or any combination of these. Described embodiments may optionally be implemented at least partly as computer software running on one or more data processors and/or digital signal processors. The elements and components of any embodiment may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the disclosed embodiments may be implemented in a single unit or may be physically and functionally distributed between different units, circuitry and/or processors.
Although the present disclosure has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognise that various features of the described embodiments may be combined in any manner suitable to implement the technique.
Number | Date | Country | Kind |
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19203127.6 | Oct 2019 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/078432 | 10/9/2020 | WO |