Mac-phy model for sidelink carrier (re)selection

Abstract

A method in a communication device having a plurality of protocol layers including a media access control, MAC, layer and a physical, PHY, layer, includes, at the MAC layer, selecting a plurality of carriers for carrier aggregation, each of the carriers being associated to a respective hybrid automatic repeat request, HARQ, entity, and at the MAC layer, initiating a sidelink carrier reselection process by the first communication device in response to a triggering event. Related devices and computer program products are disclosed.

1 . A method in a first wireless device having a plurality of protocol layers including a media access control, MAC, layer and a physical, PHY, layer, the method comprising:
 at the MAC layer, selecting a plurality of carriers for carrier aggregation, each of the carriers being associated to a respective hybrid automatic repeat request, HARQ, entity; and   at the MAC layer, initiating a carrier reselection process by the first wireless device if there is no configured sidelink grant on any carrier of the plurality of carriers.   
     
     
         2 . The method of  claim 1 , wherein each respective HARQ entity is different from a HARQ entity of each other carrier of the plurality of carriers. 
     
     
         3 . The method of  claim 1 , further comprising:
 at the MAC layer, initiating a sidelink carrier reselection process by the first wireless device in response to a triggering event, the triggering event comprising at least one of:
 there is no configured sidelink grant in any sidelink carrier; 
 a configured sidelink grant cannot accommodate a radio link control, RLC, service data unit, SDU, by using a maximum allowed modulation and coding scheme, MCS, configured by upper layers for any sidelink carrier with configured SL grant and the MAC entity selects not to segment the RLC SDU; and 
 transmission(s) with a configured sidelink grant cannot fulfil a latency requirement of data in a sidelink logical channel for any sidelink carrier with a configured sidelink grant, and the MAC selects not to perform transmission(s) corresponding to a single MAC protocol data unit, PDU. 
   
     
     
         4 . The method of  claim 3 , wherein initiating the sidelink carrier reselection process is performed only for the carrier and associated HARQ event associated with the triggering event;
 wherein the triggering event comprises at least one of:
 for a specific carrier/HARQ entity, if an SL_RESOURCE_RESELECTION_COUNTER = 0 and, when the SL_RESOURCE_RESELECTION_COUNTER was equal to 1, the MAC randomly selected, with equal probability, a value in an interval [0, 1] which is above a probability configured by upper layers; 
 neither transmission nor retransmission has been performed by MAC on any resource indicated in a configured sidelink grant during a previous second for a specific carrier/HARQ entity; 
 sl-ReselectAfter is configured and a number of consecutive unused transmission opportunities on resources indicated in the configured sidelink grant is equal to sl-ReselectAfter, for a specific carrier/HARQ entity; and/or 
 a pool of resources is configured or reconfigured by upper layers for a specific carrier. 
   
     
     
         5 . The method of  claim 3 , wherein initiating the sidelink carrier reselection process is performed for all sidelink carriers configured for sidelink operations;
 wherein the triggering event comprises at least one of:
 UE capability and/or power limitations are experienced by potential simultaneous transmissions in multiple carriers; and/or 
 transmissions with a configured sidelink grant are such that the UE is unable to listen/sense the carriers for a long time due to half duplex limitation. 
   
     
     
         6 . The method of  claim 3 , further comprising:
 after initiating the sidelink carrier reselection process, performing at least one of:
 continuing to use a previous carrier and performing resource reselection on the previous carrier; 
 selecting a second sidelink carrier and configuring a second sidelink grant on the second sidelink carrier; and 
 ceasing to use the sidelink carrier and not selecting any other sidelink carrier. 
   
     
     
         7 . The method of  claim 1  wherein the first wireless device comprises a vehicle-mounted wireless device. 
     
     
         8 . A first wireless device comprising:
 a transceiver configured to provide wireless network communication with a wireless communication network using a plurality of protocol layers including a media access control, MAC, layer; and   a processor coupled with the transceiver, wherein the processor is configured to provide wireless network communication through the transceiver, and wherein the processor is configured to perform operations comprising:
 at the MAC layer, selecting a plurality of carriers for carrier aggregation, each of the carriers being associated to a respective hybrid automatic repeat request, HARQ, entity; and 
 at the MAC layer, initiating a carrier reselection process if there is no configured sidelink grant in any carrier of the plurality of carriers. 
   
     
     
         9 . The first wireless device of  claim 8 , wherein each respective HARQ entity is different from a HARQ entity of each other carrier of the plurality of carriers. 
     
     
         10 . The first wireless device of  claim 8 , wherein the processor is configured to perform operations further comprising:
 at the MAC layer, initiating a sidelink carrier reselection process by the first wireless device in response to a triggering event, the triggering event comprising at least one of:
 there is no configured sidelink grant in any sidelink carrier; 
 a configured sidelink grant cannot accommodate a radio link control, RLC, service data unit, SDU, by using a maximum allowed modulation and coding scheme, MCS, configured by upper layers for any sidelink carrier with configured SL grant and the MAC entity selects not to segment the RLC SDU; and 
 transmission(s) with a configured sidelink grant cannot fulfil a latency requirement of data in a sidelink logical channel for any sidelink carrier with a configured sidelink grant, and the MAC selects not to perform transmission(s) corresponding to a single MAC protocol data unit, PDU. 
   
     
     
         11 . The first wireless device of  claim 10 , wherein initiating the sidelink carrier reselection process is performed only for the carrier and associated HARQ event associated with the triggering event;
 wherein the triggering event comprises at least one of:
 for a specific carrier/HARQ entity, if an SL_RESOURCE_RESELECTION_COUNTER = 0 and, when the SL_RESOURCE_RESELECTION_COUNTER was equal to 1, the MAC randomly selected, with equal probability, a value in an interval [0, 1] which is above a probability configured by upper layers; 
 neither transmission nor retransmission has been performed by MAC on any resource indicated in a configured sidelink grant during a previous second for a specific carrier/HARQ entity; 
 sl-ReselectAfter is configured and a number of consecutive unused transmission opportunities on resources indicated in the configured sidelink grant is equal to sl-ReselectAfter, for a specific carrier/HARQ entity; and/or 
 a pool of resources is configured or reconfigured by upper layers for a specific carrier. 
   
     
     
         12 . The first wireless device of  claim 10 , wherein initiating the sidelink carrier reselection process is performed for all sidelink carriers configured for sidelink operations;
 wherein the triggering event comprises at least one of:
 UE capability and/or power limitations are experienced by potential simultaneous transmissions in multiple carriers; and/or 
 transmissions with a configured sidelink grant are such that the UE is unable to listen/sense the carriers for a long time due to half duplex limitation. 
   
     
     
         13 . The first wireless device of  claim 10 , further comprising:
 after initiating the sidelink carrier reselection process, performing at least one of:
 continuing to use a previous carrier and performing resource reselection on the previous carrier; 
 selecting a second sidelink carrier and configuring a second sidelink grant on the second sidelink carrier; and 
 ceasing to use the sidelink carrier and not selecting any other sidelink carrier. 
   
     
     
         14 . The first wireless device of  claim 8  wherein the first wireless device is a vehicle mounted wireless device. 
     
     
         15 . A non-transitory storage medium including program code to be executed by processing circuitry of a first wireless device configured to operate in a communication network, whereby execution of the program code causes the first wireless device to perform operations comprising:
 at the MAC layer, selecting a plurality of carriers for carrier aggregation, each of the carriers being associated to a respective hybrid automatic repeat request, HARQ, entity; and   at the MAC layer, initiating a carrier reselection process by the first wireless device if there is no configured sidelink grant on any carrier of the plurality of carriers.   
     
     
         16 . The non-transitory storage medium of  claim 15 , including further program code to be executed by processing circuitry whereby execution of the further program code causes the first wireless device to perform operations comprising wherein in selecting the plurality of carriers, each respective HARQ entity is different from a HARQ entity of each other carrier of the plurality of carriers. 
     
     
         17 . The non-transitory storage medium of  claim 15 , wherein the non-transitory storage medium includes further program code to be executed by processing circuitry whereby execution of the further program code causes the first wireless device to perform operations further comprising:
 at the MAC layer, initiating a sidelink carrier reselection process by the first wireless device in response to a triggering event, the triggering event comprising at least one of:
 there is no configured sidelink grant in any sidelink carrier; 
 a configured sidelink grant cannot accommodate a radio link control, RLC, service data unit, SDU, by using a maximum allowed modulation and coding scheme, MCS, configured by upper layers for any sidelink carrier with configured SL grant and the MAC entity selects not to segment the RLC SDU; and 
 transmission(s) with a configured sidelink grant cannot fulfil a latency requirement of data in a sidelink logical channel for any sidelink carrier with a configured sidelink grant, and the MAC selects not to perform transmission(s) corresponding to a single MAC protocol data unit, PDU. 
   
     
     
         18 . The non-transitory storage medium of  claim 15 , wherein the non-transitory storage medium includes further program code to be executed by processing circuitry whereby execution of the further program code causes the first wireless device to perform operations further comprising: wherein initiating the sidelink carrier reselection process is performed only for the carrier and associated HARQ event associated with the triggering event;
 wherein the triggering event comprises at least one of:
 for a specific carrier/HARQ entity, if an SL_RESOURCE_RESELECTION_COUNTER = 0 and, when the SL_RESOURCE_RESELECTION_COUNTER was equal to 1, the MAC randomly selected, with equal probability, a value in an interval [0, 1] which is above a probability configured by upper layers; 
 neither transmission nor retransmission has been performed by MAC on any resource indicated in a configured sidelink grant during a previous second for a specific carrier/HARQ entity; 
 sl-ReselectAfter is configured and a number of consecutive unused transmission opportunities on resources indicated in the configured sidelink grant is equal to sl-ReselectAfter, for a specific carrier/HARQ entity; and/or 
 a pool of resources is configured or reconfigured by upper layers for a specific carrier. 
   
     
     
         19 . The non-transitory storage medium of  claim 15 , wherein the non-transitory storage medium includes further program code to be executed by processing circuitry whereby execution of the further program code causes the first wireless device to perform operations further comprising: wherein initiating the sidelink carrier reselection process is performed for all sidelink carriers configured for sidelink operations;
 wherein the triggering event comprises at least one of:
 UE capability and/or power limitations are experienced by potential simultaneous transmissions in multiple carriers; and/or 
 transmissions with a configured sidelink grant are such that the UE is unable to listen/sense the carriers for a long time due to half duplex limitation. 
   
     
     
         20 . The non-transitory storage medium of  claim 15 , wherein the non-transitory storage medium includes further program code to be executed by processing circuitry whereby execution of the further program code causes the first wireless device to perform operations further comprising:
 after initiating the sidelink carrier reselection process, performing at least one of:
 continuing to use a previous carrier and performing resource reselection on the previous carrier; 
 selecting a second sidelink carrier and configuring a second sidelink grant on the second sidelink carrier; and 
 ceasing to use the sidelink carrier and not selecting any other sidelink carrier.