Eps bearer splitting for dual connectivity devices

Abstract

A User Equipment (UE) may be connected to multiple Enhanced Node Bs (eNBs). The multiple connection allows a UE to have an EPS bearer with multiple bearer paths, one routed through each of the eNBs. One eNB may implement a decision module to switch the bearer path to route incoming packets along a selected bearer path in order to achieve objectives such as maintaining Quality of Service (QoS) for the EPS bearer and/or maximizing overall network throughput. The eNB may gather information and metrics influencing these objectives from the other eNB and UE in order to make better bearer path decisions. The split bearer allows the UE to implement reduced protocol layers and reconfigure the protocol layers to match the bearer path selected by the eNB.

What is claimed is: 
     
         1 . A method performed by user equipment (UE), the method comprising:
 receiving information packets over a first bearer path from a first enhanced node B (eNB);   identifying a decision point where a switch from the first bearer path to a second bearer path is possible, a second eNB using the second bearer path; and   responsive to the decision point and to decision logic, reconfiguring the UE to receive packets via the second bearer path when the decision logic indicates that the first eNB will route packets to the second bearer path via the second eNB.   
     
     
         2 . The method of  claim 1 , wherein the decision logic indicates that the first eNB will route packets to the second bearer path via the second eNB upon expiration of a time slot. 
     
     
         3 . The method of  claim 1 , wherein the decision logic indicates that the first eNB may route packets to the second bearer path via the second eNB upon expiration of a time slot and wherein the method further comprises listening to both the first and second bearer path upon expiration of the time slot to identify which bearer path is being used by the first eNB to route packets to the UE. 
     
     
         4 . The method of  claim 1 , further comprising receiving via the first bearer path a last packet indication and wherein the decision logic indicates that the first eNB will route packets to the second bearer path via the second eNB upon. 
     
     
         5 . The method of  claim 1  further comprising sending to the first eNB at least one of:
 a metric relating to channel quality indicator (CQI); 
 a metric relating to Hybrid Automatic Repeat Request (HARQ); and 
 a metric relating to a delay estimate. 
 
     
     
         6 . An enhanced Node B (eNB) comprising:
 processing circuitry configured to:
 obtain Quality of Service (QoS) information for a first bearer path which provides packets to a User Equipment (UE) via the eNB and a second bearer path which provides packets to the UE via a second eNB; 
 identify a switch event, the occurrence of which causes the eNB to identify a selected bearer path from among the first bearer path or second bearer path to send packets to the UE; 
 responsive to the switch event and to selection criteria, identify the selected bearer path; and 
 route packets to the UE via the selected bearer path. 
   
     
     
         7 . The eNB of  claim 6 , wherein the switch event comprises the expiration of a time slot and wherein the selection criteria identifies the selected bearer path as a currently non-selected bearer path. 
     
     
         8 . The eNB of  claim 6 , further comprising:
 establishing a schedule to receive at least one metric;   responsive to the switch event and the selection criteria, when the selected bearer path is the first bearer path:
 notifying the second eNB of the decision to switch from the second bearer path and the first bearer path; and 
 receiving from the second eNB a last packet notification indicating that a last packet has been sent to the UE; 
   responsive to the switch event and the selection criteria, when the selected bearer path is the second bearer path:
 sending the last packet notification to the UE upon transmission of the last packet via the first bearer path. 
   
     
     
         9 . The eNB of  claim 6 , wherein the selection criteria comprises at least one of:
 maintaining QoS of the selected bearer path; and   maximizing overall network capacity.   
     
     
         10 . The eNB of  claim 6 , wherein the selection criteria considers factors comprising at least one of:
 UE channel conditions;   load estimate of at least one of the eNB and second eNB; and   at least one delay estimate.   
     
     
         11 . The eNB of  claim 10 , wherein the delay estimate comprises at least one of:
 an over the air delay from at least one of the eNB and the second eNB to the UE;   an overall bearer processing delay; and   a backhaul delay.   
     
     
         12 . A method executed by an enhanced Node B (eNB) comprising:
 obtaining metrics influencing at least one bearer path, the metrics comprising at least one of:
 a Channel Quality Indicator (CQI); 
 a load estimate; and 
 a delay estimate; 
   obtaining Quality of Service (QoS) requirements for a bearer having a first bearer path and a second bearer path;   calculating an efficiency factor for each of the first bearer path and the second bearer path based on the metrics; and   selecting, based on the efficiency factor, either the first bearer path or the second bearer path to route packets to a User Equipment.   
     
     
         13 . The method of  claim 12 , further comprising:
 identifying a switch event where selection of either the first bearer path or the second bearer path may be changed;   recalculating the efficiency factor for each of the first bearer path and the second bearer path;   responsive to occurrence of the switch event, selecting either the first bearer path or the second bearer path to route packets to the UE based on the recalculated efficiency factor for each of the first bearer path and the second bearer path.   
     
     
         14 . The method of  claim 12  wherein the CQI is obtained from the UE. 
     
     
         15 . The method of  claim 12 , wherein the load estimate comprises at least one of:
 radio bearer usage;   hardware loading factor; and   number of bearers being served.   
     
     
         16 . The method of  claim 12 , wherein the delay estimate comprises at least one of:
 Hybrid Automatic Repeat Request (HARQ) metrics to indicate over the air delay;   Radio Link Control (RLC) delay;   Packet Data Convergence Protocol (PDCP) delay; and   backhaul delay.   
     
     
         17 . The method of  claim 12 , wherein selecting either the first bearer path or the second bearer path to route packets to a User Equipment comprises:
 setting a selected efficiency factor as the efficiency factor for the selected one of the first bearer path or the second bearer path;   setting a non-selected efficiency factor as the efficiency factor for the non-selected one of the first bearer path or the second bearer path;   comparing the selected efficiency factor to the non-selected efficiency factor plus a threshold value; and   switching to the non-selected one of the first bearer path or the second bearer path when the non-selected efficiency factor plus a threshold exceeds the selected efficiency factor.   
     
     
         18 . User Equipment (UE) comprising:
 at least one antenna;   transceiver circuitry coupled to the at least one antenna;   memory;   a processor coupled to the memory and transceiver circuitry; and   instructions, stored in the memory, which when executed cause the processor to perform actions comprising:
 receive information packets over a first bearer path from a first enhanced node B (eNB); 
 identify a decision point where a switch from the first bearer path to a second bearer path is possible, a second eNB using the second bearer path; and 
 responsive to the decision point and to decision logic, reconfigure the UE to receive packets via the second bearer path when the decision logic indicates that the first eNB will route packets to the second bearer path via the second eNB. 
   
     
     
         19 . The UE of  claim 18 , wherein the decision logic indicates that the first eNB may route packets to the second bearer path via the second eNB upon occurrence of a switch event and wherein the instructions further cause the processor to listen to both the first and second bearer path upon occurrence of the switch event to identify which bearer path is being used by the first eNB to route packets to the UE. 
     
     
         20 . The UE of  claim 18 , further comprising receiving via the first bearer path a last packet indication and wherein the decision logic indicates that the first eNB will route packets to the second bearer path via the second eNB upon.