Buffer status report and logical channel prioritization for dual connectivity
Apparatus and methods are provided to enhance BSR and LCP procedures for the dual connectivity system. In one novel aspect, the BSR is handled for each MAC entity according to one or more allocation rules. In one embodiment, the allocation rule is configured by the network. In another embodiment, the allocation rule is determined by the UE based on historic statics. In yet another embodiment, the allocation rule is determined by the UE based on information from the network. In one embodiment, the allocation rule indicates percentage of traffic allocated to each MAC entity. In another novel aspect, LCP is performed independently for each MAC entity if the split bearer is configured and the prioritized bit rate (PBR) and the bucket size duration (BSD) are signaled for each eNB. In one embodiment, separate sets of LCG variables are maintained independently for each MAC entity.
1. A method comprising:
configuring a macro cell group (MCG) by a user equipment (UE) in a wireless network, wherein the MCG is served by a first medium access control (MAC) entity including serving cells associating with a macro base station;
configuring a secondary cell group (SCG) served by a second MAC entity of the UE, wherein the SCG includes serving cells associating with a secondary base station;
determining an amount of available data for transmission based on a status protocol data unit (PDU) and/or a state of a status prohibit timer,
wherein when the status PDU is triggered and/or the status prohibit timer is expired, determining that the amount of available data for transmission includes a sum of data for the first MAC entity and a size of the PDU; and
calculating a MCG buffer status value for the first MAC entity and a SCG buffer status value for the second MAC based on an allocation rule and the determined amount of available data for transmission, wherein the allocation rule is based on one of: (i) an uplink (UL) data path configuration, (ii) a split threshold configuration, and (iii) local throughput statistics of buffered data for transmission by the UE.
2. The method of claim 1 , wherein the allocation rule indicates a percentage of traffic to be transmitted by the MCG.
3. The method of claim 2 , wherein the percentage of traffic is configured by a network entity.
4. The method of claim 2 , wherein the percentage of traffic is determined by the UE based on the local throughput statistics of the buffered data for transmission by the UE.
5. The method of claim 2 , wherein the percentage of traffic is determined by the UE based on information received from the macro base station.
6. The method of claim 2 , wherein the MCG buffer status value includes a size of the available data for transmission times the percentage of traffic configured for the MCG, and wherein the SCG buffer status value includes the remaining available data for transmission.
7. The method of claim 1 , wherein the allocation rule is based on an UL data path configured by upper layer, and wherein the MCG buffer status value includes the size of all available data for transmission if the UL data path is configured to be SCG, otherwise, the SCG buffer status value includes the size of all available data for transmission.
8. The method of claim 1 , wherein the allocation rule is based on a configured split threshold for available data for transmission, and wherein the MCG buffer status value includes the size of all available data for transmission if the size of available data for transmission is smaller than the split threshold.
9. The method of claim 1 , wherein available data for transmission includes service data units (SDUs) not submitted to lower layers that has not been processed by Packet Data Convergence Protocol (PDCP) of the UE, and PDUs if their corresponding SDUs has been processed by PDCP.
10. An user equipment (UE), comprising:
a transceiver that transmits and receives radio signals from one or more base stations in a wireless network;
a first medium access control (MAC) entity that serves a macro cell group (MCG) including serving cells associating with a macro base station;
a second MAC entity that serves a secondary cell group (SCG) including serving cells associating with a secondary base station;
a transmission data circuit that determines an amount of available data for transmission based on a status protocol data unit (PDU) and/or a state of a status prohibit timer,
wherein when the status PDU is triggered and/or the status prohibit timer is expired, determining that the amount of available data for transmission includes a sum of data for the first MAC entity and a size of the PDU; and
a buffer status report (BSR) circuit that calculates a MCG buffer status value for the first MAC entity and a SCG buffer status value for the second MAC based on an allocation rule and the determined amount of available data for transmission, wherein the allocation rule is based on one of: (i) an uplink (UL) data path configuration, (ii) a split threshold configuration, and (iii) local throughput statistics of buffered data for transmission by the UE.
11. The UE of claim 10 , wherein the allocation rule indicates a percentage of traffic to be transmitted by the MCG.
12. The UE of claim 11 , wherein the percentage of traffic is configured by a network entity.
13. The UE of claim 11 , wherein the percentage of traffic is determined by the UE based on the local throughput statistics of the buffered data for transmission by the UE.
14. The UE of claim 11 , wherein the percentage of traffic is determined by the UE based on information received from the macro base station.
15. The UE of claim 11 , wherein the MCG buffer status value includes a size of the available data for transmission times the percentage of traffic configured for the MCG, and wherein the SCG buffer status value includes the remaining available data for transmission.
16. The UE of claim 10 , wherein the allocation rule is based on an UL data path configured by upper layer, and wherein the MCG buffer status value includes the size of all available data for transmission if the UL data path is configured to be SCG, otherwise, the SCG buffer status value includes the size of all available data for transmission.
17. The UE of claim 10 , wherein the allocation rule is based on a configured split threshold for available data for transmission, and wherein the MCG buffer status value includes the size of all available data for transmission if the size of available data for transmission is smaller than the split threshold.
18. The UE of claim 10 , wherein available data for transmission includes service data units (SDUs) not submitted to lower layers that has not been processed by Packet Data Convergence Protocol (PDCP) of the UE, and PDUs if their corresponding SDUs has been processed by PDCP.