Method and apparatus for relay load information determination and relay selection
Embodiments of the present disclosure provide method and apparatus for relay load information determination and relay selection. A method performed by a first terminal device includes obtaining relay load information of the first terminal device. The method further includes transmitting the relay load information of the first terminal device to a second terminal device.
1 . A method performed by a first terminal device, comprising:
obtaining relay load information of the first terminal device, wherein the relay load information of the first terminal device comprises information regarding free bandwidth that the first terminal device can provide for relay traffic, wherein the free bandwidth that the first terminal device can provide for relay traffic is determined as:
a maximum bandwidth of the first terminal device in the Uu interface of the first terminal device minus a bandwidth for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device, or
a maximum bandwidth of the first terminal device in the PC5 interface of the first terminal device minus a bandwidth for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device; and
transmitting the relay load information of the first terminal device to a second terminal device.
2 . The method according to claim 1 , wherein the relay load information of the first terminal device further comprises at least one of:
information regarding achievable bit rate that the first terminal device can provide for relay traffic,
information regarding remained available sidelink resource for dedicated resource pools in a cell,
an average number of destination layer 2 identifiers to which the first terminal device has data to transmit,
an average number of destination layer 2 identifiers to which the first terminal device has an PC5 unicast connection,
a ratio between capacity that the first terminal device can achieve over a Uu interface of the first terminal device and capacity that the first terminal device can achieve over a PC5 interface of the first terminal device, or
a capacity value that the first terminal device can achieve over the Uu interface of the first terminal device and a capacity value that the first terminal device can achieve over the PC5 interface of the first terminal device.
3 . The method according to claim 2 , wherein the achievable bit rate that the first terminal device can provide for relay traffic is determined as a maximum bit rate of the first terminal device in the Uu interface of the first terminal device minus a bit rate for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device; or
wherein the achievable bit rate that the first terminal device can provide for relay traffic is determined as a maximum bit rate of the first terminal device in the PC5 interface of the first terminal device minus a bit rate for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device.
4 . The method according to claim 3 , wherein the maximum bandwidth and/or the maximum bit rate of the first terminal device in the Uu interface of the first terminal device is determined based on at least one quality of service (QoS) requirement for the Uu interface of the first terminal device;
wherein the at least one QoS requirement for the Uu interface of the first terminal device comprises at least one of:
session aggregate maximum bit rate (AMBR),
user equipment (UE)-AMBR,
guaranteed flow bit rate (GFBR),
maximum flow bit rate (MFBR), or
maximum data burst volume (MDBV).
5 . The method according to claim 4 , wherein the maximum bandwidth and/or the maximum bit rate of the first terminal device in the Uu interface of the first terminal device is set as a summarized value of QoS requirements of all sessions or flows in the Uu interface of the first terminal device; or
wherein the maximum bandwidth and/or the maximum bit rate of the first terminal device in the Uu interface of the first terminal device is determined based on one or more prioritized sessions or flows in the Uu interface of the first terminal device.
6 . The method according to claim 1 , wherein the maximum bandwidth and/or the maximum bit rate of the first terminal device in the Uu interface of the first terminal device is determined based on at least one of:
a mobility state of the first terminal device,
a location of the first terminal device,
uplink grants that the network device has assigned to the first terminal device,
downlink assignments that the network device has assigned to the first terminal device,
a measured uplink radio channel quality indicator, or
a measured downlink radio channel quality indicator;
wherein a radio channel quality indicator comprises at least one of:
reference signal receiving power (RSRP),
reference signal receiving quality (RSRQ),
reference signal strength indicator (RSSI),
signal to interference plus noise ratio (SINR),
signal to interference ratio (SIR),
channel occupancy,
channel busy ratio, or
channel usage ratio.
7 . The method according to claim 1 , wherein obtaining relay load information of the first terminal device comprises:
determining the relay load information of the first terminal device;
receiving information regarding maximum bandwidth and/or maximum bit rate of the first terminal device in a Uu interface of the first terminal device from a network device.
8 . The method according to claim 1 , wherein the maximum bandwidth and/or the maximum bit rate of the first terminal device in the Uu interface of the first terminal device is determined based on capabilities of the first terminal device;
wherein the bandwidth and/or the bit rate for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device is determined based on at least one quality of service (QoS) requirement for the PC5 interface of the first terminal device;
wherein the at least one QoS requirement for the PC5 interface of the first terminal device comprises at least one of:
session aggregate maximum bit rate (AMBR),
PC5 link AMBR,
UE-PC5-AMBR,
guaranteed flow bit rate (GFBR),
maximum flow bit rate (MFBR), or
maximum data burst volume (MDBV).
9 . The method according to claim 1 , wherein the bandwidth and/or the bit rate for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device is set as a summarized value of QoS requirements of all sessions or flows carrying relay traffic in the PC5 interface of the first terminal device; or
wherein the bandwidth and/or the bit rate for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device is determined based on one or more prioritized sessions or flows carrying relay traffic in the PC5 interface of the first terminal device.
10 . The method according to claim 1 , wherein the bandwidth and/or the bit rate for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device is determined based on capabilities of the first terminal device.
11 . The method according to claim 8 , wherein the capabilities of the first terminal device comprises at least one of:
whether the first terminal device supports multiple input multiple output (MIMO) based transmissions and/or receptions,
a maximum number of supported layers in case of MIMO based transmissions and/or receptions,
a maximum number of component carriers or serving cells are supported in multi-connectivity or carrier aggregation scenarios,
a maximum supported modulation order,
supported numerologies,
a maximum resource block (RB) allocation in bandwidth for transmissions and/or receptions,
an overhead factor, or
a scaling factor for limiting relay traffic in the Uu interface of the first terminal device.
12 . The method according to claim 2 , wherein the information regarding remained available sidelink resource for dedicated resource pools in a cell comprises at least one of:
a ratio of remained available sidelink resource averaged over all dedicated resource pools in the cell, or
a value of aggregated available sidelink resource remained in all dedicated resource pools in the cell.
13 . The method according to claim 2 , further comprising:
receiving the information regarding remained available sidelink resource for dedicated resource pools in the cell from a network device.
14 . The method according to claim 2 , further comprising:
transmitting a special value to the second terminal device, wherein the special value indicates that the first terminal device is in radio resource control (RRC) idle or inactive state.
15 . The method according to claim 2 , wherein the average number of destination layer 2 identifier to which the first terminal device has data to transmit comprises at least one of:
an average number of destination layer 2 identifier to which the first terminal device has relayed data to transmit, or
an average number of destination layer 2 identifier to which the first terminal device has non-relayed data to transmit,
an average number of destination layer 2 identifier to which the first terminal device has relayed data and non-relayed data to transmit.
16 . The method according to claim 2 , wherein the capacity that the first terminal device can achieve over the Uu interface of the first terminal device or the PC5 interface of the first terminal device is calculated based on at least one of:
a supported max data rate,
a total layer 2 buffer size,
a number of data radio bearers currently used out of a maximum supported by the capability of the first terminal device,
a max throughput over the Uu interface of the first terminal device,
a max throughput over the PC5 interface of the first terminal device, or
a ratio between capacity that the first terminal device can achieve over the Uu interface of the first terminal device and the PC5 interface of the first terminal device;
wherein a maximum bandwidth and/or a maximum bit rate of the first terminal device in the Uu interface of the first terminal device and/or information regarding remained available sidelink resource for dedicated resource pools in a cell is received from a network device via at least one of:
system information,
a paging message,
a control protocol data unit of a protocol layer,
an adaptation layer,
downlink control information (DCI),
medium access control (MAC) control element (CE),
a dedicated radio resource control signaling, or
a handover command.
17 . The method according to claim 1 , wherein the relay load information of the first terminal device is transmitted to the second terminal device via at least one of:
PC5-radio resource control,
PC5-signaling,
a discovery message,
a control protocol data unit of a protocol layer,
an adaptation layer,
MAC CE,
sidelink control information.
18 . The method according to claim 1 , wherein the relay load information comprises at least one of:
relay load information for uplink relay traffic, or
relay load information for downlink relay traffic.
19 . A first terminal device, comprising:
a processor; and
a memory coupled to the processor, the memory containing instructions executable by the processor to:
obtain relay load information of the first terminal device, wherein the relay load information of the first terminal device comprises an average number of destination layer 2 identifiers to which the first terminal device has data to transmit, wherein the average number of destination layer 2 identifier to which the first terminal device has data to transmit comprises at least one of:
an average number of destination layer 2 identifier to which the first terminal device has relayed data to transmit,
an average number of destination layer 2 identifier to which the first terminal device has non-relayed data to transmit, or
an average number of destination layer 2 identifier to which the first terminal device has relayed data and non-relayed data to transmit; and
transmit the relay load information of the first terminal device to a second terminal device.
20 . A method performed by a first terminal device, comprising:
obtaining relay load information of the first terminal device, wherein the relay load information of the first terminal device comprises information regarding achievable bit rate that the first terminal device can provide for relay traffic, wherein the achievable bit rate that the first terminal device can provide for relay traffic is determined as:
a maximum bit rate of the first terminal device in the Uu interface of the first terminal device minus a bit rate for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device, or
a maximum bit rate of the first terminal device in the PC5 interface of the first terminal device minus a bit rate for relay traffic occupied by at least one second terminal device which is connected to the first terminal device in the PC5 interface of the first terminal device; and
transmitting the relay load information of the first terminal device to a second terminal device.