Apparatus and method for link adaptation in uplink grant-less random access
Embodiments are provided for a scheme of link adaptation (LA) in uplink grant-less random access (RA) communications. The scheme includes changing a modulation and coding (MCS) of a user, instead of using a fixed MCS over time, as the user link, channel, or non-link conditions vary during the RA communications. In an embodiment, a transmission point (TP) receives from a UE a packet encoded using a MCS, and detects a condition associated with uplink measurements or other non-link based condition of the UE. The TP then initiates an upgrade or a downgrade of the MCS in accordance with the condition, and signals the UE indicating a second MCS as a result. The UE thus sends a second packet encoded using the second MCS. In another embodiment, the UE initiates the MCS change in accordance to detecting a link or non-link based condition, such as change of mobility.
1. A method for realizing device-to-device communication relay selection, comprising:
receiving, by a user equipment, relay-related information sent by a relay node; selecting or configuring, by the user equipment, an access relay node; and
in response to determining that the user equipment has not selected the access relay node, or the user equipment has already selected the access relay node and a measurement result that is obtained by the user equipment by performing a measurement on the relay-related information sent by the selected access relay node is less than a relay reselection device-to-device communication link threshold, the user equipment monitoring a relay reception resource pool and receiving the relay-related information sent by the relay node,
wherein the relay-related information comprises at least one of:
a relay usable time period of the relay node;
a relay charging demand of the relay node.
2. The method of claim 1 , wherein the network component is one of a base station or a network controller.
3. The method of claim 1 , further comprising:
before the assigning the first MCS, assigning, to the UE, an initial MCS of the second plurality of MCSs based on the second LUT and the UE;
receiving, from the UE, an initial packet encoded using the initial MCS; and
measuring the first link quality based on the received initial packet.
4. The method of claim 1 , wherein the plurality of link qualities are a plurality of channel quality indicator (CQI) values.
5. The method claim 1 , further comprising:
before the assigning, measuring the first link quality associated with the UE; and after the assigning, transmitting the first MCS to the UE via a radio resource control (RRC) signal.
6. The method of claim 1 , further comprising:
measuring a second link quality associated with the UE, the second link quality being higher than the first link quality;
assigning, by the network component to the UE, a second MCS of the first plurality of MCSs based on the first LUT and the second link quality, the second MCS being less robust than the first MCS; and
receiving, from the UE, a second packet encoded using the second MCS.
7. The method of claim 6 , further comprising:
measuring a third link quality associated with the UE, the third link quality being lower than the first link quality;
assigning, by the network component to the UE, a third MCS of the first plurality of MCSs based on the first LUT and the third link quality, the third MCS being more robust than the first MCS; and
receiving, from the UE, a third packet encoded using the third MCS.
8. The method of claim 1 , further comprising:
transmitting, to the UE, a link adaptation (LA) condition associated with UE transmission or application quality, wherein the LA condition comprises one or more of a long-term link quality measurement, a mobility of the UE, or a quality of service (QoS) requirement for an application of the UE.
9. The method of claim 1 , wherein the first LUT is used for slow link adaptation (LA), and the second LUT is used for short term LA.
10. A network component for link adaptation, the network component comprising:
at least one processor; and
a non-transitory computer readable storage medium storing programming for execution by the at least one processor, the programming including instructions for:
establishing a first look-up table (LUT) associating a plurality of link qualities with a first plurality of modulation and coding schemes (MCSs);
establishing a second LUT associating a plurality of user equipments (UEs) with a second plurality of MCSs, wherein a number of entries in the first LUT is fewer than a number of entries in the second LUT;
assigning, to a UE, a first MCS of the first plurality of MCSs based on the first LUT and a first link quality associated with the UE; and
receiving, from the UE, a first packet in a grant free transmission, the first packet encoded using the first MCS assigned by the network component.
11. A method for realizing device-to-device communication relay selection, comprising:
sending or preconfiguring, by a network control node through broadcasting or dedicated signaling, a relay reception resource pool and/or a relay selection threshold, to make a user equipment receive relay-related information sent by a relay node and select or configure an access relay node; wherein the relay selection threshold comprises a relay reselection hysteresis value; and wherein the relay-related information comprises at least one of:
a relay usable time period of the relay node; and
a relay charging demand of the relay node.
12. The network component of claim 10 , the programming further including instructions for:
before the assigning the first MCS, assigning, to the UE, an initial MCS of the second plurality of MCSs based on the second LUT and the UE;
receiving, from the UE, an initial packet encoded using the initial MCS; and
measuring the first link quality based on the received initial packet.
13. A user equipment, comprising a processor and a storage device, wherein the storage device communicably connected with the processor and configured for storing processor-executable instructions executable by the processor; wherein the processor-executable instructions when executed by the processor causes the processor to perform a method for realizing device-to-device communication relay selection, wherein the method comprises:
receiving, by a user equipment, relay-related information sent by a relay node; and selecting or configuring, by the user equipment, an access relay node;
in response to determining that the user equipment has not selected the access relay node, or the user equipment has already selected the access relay node and a measurement result that is obtained by the user equipment by performing a measurement on the relay-related information sent by the selected access relay node is less than a relay reselection device-to-device communication link threshold, the user equipment monitoring a relay reception resource pool and receiving the relay-related information sent by the relay node,
wherein the relay-related information comprises at least one of:
a relay usable time period of the relay node;
a relay charging demand of the relay node.
14. The network component of claim 10 , the programming further including instructions for:
before the assigning, measuring the first link quality associated with the UE; and
after the assigning, transmitting the first MCS to the UE via a radio resource control (RRC) signal.
15. The network component of claim 10 , the programming further including instructions for:
measuring a second link quality associated with the UE, the second link quality being higher than the first link quality;
assigning, to the UE, a second MCS of the first plurality of MCSs based on the first LUT and the second link quality, the second MCS being less robust than the first MCS; and
receiving, from the UE, a second packet encoded using the second MCS.
16. The network component of claim 15 , the programming further including instructions for:
measuring a third link quality associated with the UE, the third link quality being lower than the first link quality;
assigning, to the UE, a third MCS of the first plurality of MCSs based on the first LUT and the third link quality, the third MCS being more robust than the first MCS; and
receiving, from the UE, a third packet encoded using the third MCS.
17. The network component of claim 10 , the programming further including instructions for:
transmitting, to the UE, a link adaptation (LA) condition associated with UE transmission or application quality, wherein the LA condition comprises one or more of a long-term link quality measurement, a mobility of the UE, or a quality of service (QoS) requirement for an application of the UE.
18. The network component of claim 10 , wherein the first LUT is used for slow link adaptation (LA), and the second LUT is used for short term LA.
19. A non-transitory computer-readable device having instructions stored thereon that, when executed by a network component, cause the network component to perform operations, the operations comprising:
establishing a first look-up table (LUT) associating a plurality of link qualities with a first plurality of modulation and coding schemes (MCSs);
establishing a second LUT associating a plurality of user equipments (UEs) with a second plurality of MCSs, wherein a number of entries in the first LUT is fewer than a number of entries in the second LUT;
assigning, to a UE, a first MCS of the first plurality of MCSs based on the first LUT and a first link quality associated with the UE; and
receiving, from the UE, a first packet in a grant free transmission, the first packet encoded using the first MCS assigned by the network component.
20. The non-transitory computer-readable device of claim 19 , wherein the network component is one of a base station or a network controller.
21. The method of claim 1 , wherein the first link quality is based on an uplink (UL) channel measurement of a reference signal, and wherein the reference signal comprises a sounding reference signal (SRS).