Systems, methods, and devices for reduced handover data interruption
User equipment (UE) handover (HO) techniques for reducing or eliminating interruption time during an HO process are described. In one embodiment, for example, an apparatus may include at least one memory and logic for an evolved node B (eNB), at least a portion of the logic comprised in hardware coupled to the at least one memory. The logic may be operative to forward downlink (DL) data received from a serving gateway (SGW) to user equipment (UE), transmit a handover command to the UE to trigger execution of a handover (HO) process to handover the UE to a target eNB, continue forwarding at least a portion of the DL data to the UE following transmission of the handover command, and terminate transmission of the DL data to the UE responsive to detecting a stop DL data event. Other embodiments are described and claimed.
1. An apparatus of a base station configured as a source base station, comprising:
at least one memory; and
logic for the source base station, the logic comprised in hardware coupled to the at least one memory, the logic configured to:
initiate a handover (HO) process via a handover command to handover a user equipment (UE) to a target base station,
provide downlink (DL) data to the UE following transmission of the HO command,
initiate an HO event timer and access event estimate information to estimate the occurrence of the HO event, the event estimate information comprising an expected time duration between two time events or a time-of-day value;
provide DL data to the target base station responsive to detecting a forward DL data event during the HO process;
detect a stop DL data event by estimating an occurrence of an HO event during the HO process; and
terminate providing the DL data to the UE responsive to detecting the stop DL data event, the stop DL data event comprising receipt of a message from the target base station that the UE receives DL data from the target base station.
2. The apparatus of claim 1 , the forward DL data event comprising at least one of transmission of the HO command to the UE, performance of a random access channel (RACH) procedure by the UE, receipt of a random access response (RAR) message by the UE, and the UE accessing the target base station.
3. The apparatus of claim 1 , the logic further configured to provide a sequence number (SN) transfer message to the target base station responsive to detecting an SN status transfer event during the HO process.
4. The apparatus of claim 3 , the SN status transfer event comprising at least one of the UE not receiving packet data, the UE accessing the target base station, and the target base station sending confirmation to the source base station that the UE has completed the HO process.
5. A non-transitory computer-readable storage medium that stores instructions for execution by processing circuitry of a base station, the instructions to cause the base station to:
operate as a source base station during a handover (HO) process handing over a user equipment (UE) to a target base station;
provide downlink (DL) data to the UE following transmission of an HO command to the UE;
initiate an HO event timer and access event estimate information to estimate the occurrence of the HO event, the event estimate information comprising an expected time duration between two time events or a time-of-day value;
forward DL data to the target base station responsive to detecting a forward DL data event during the HO process;
detect one of stop DL data events during the HO process by estimating an occurrence of the HO event; and
terminate providing of the DL data to the UE responsive to the detecting of one of the stop DL data events;
wherein the stop DL data events comprises a first stop DL data event of loss of acknowledgment for DL data from the UE and a second stop DL data event of loss of status report from the UE.
6. The non-transitory computer-readable storage medium of claim 5 , the forward DL data event comprising at least one of transmission of the HO command to the UE, performance of a random access channel (RACH) procedure by the UE, receipt of a random access response (RAR) message by the UE, and the UE accessing the target base station.
7. The non-transitory computer-readable storage medium of claim 5 , the instructions to cause the source base station to transmit a sequence number (SN) transfer message to the target base station responsive to detecting an SN status transfer event during the HO process.
8. The non-transitory computer-readable storage medium of claim 7 , the SN status transfer event comprising at least one of the UE not receiving packet data, the UE accessing the target base station, and the target base station sending confirmation to the source base station that the UE has completed the HO process.
9. An apparatus of a source base station, comprising:
at least one memory; and
logic for the source base station, the logic comprised in hardware coupled to the at least one memory, the logic configured to:
initiate a handover (HO) process via a handover command to handover a user equipment (UE) to a target base station,
provide downlink (DL) data to the UE following transmission of the HO command,
initiate an HO event timer and access event estimate information to estimate the occurrence of the HO event, the event estimate information comprising an expected time duration between two time events or a time-of-day value;
provide DL data to the target base station responsive to detecting a forward DL data event during the HO process;
detect one of a set of stop DL data event by estimating an occurrence of an HO event during the HO process; and
terminate providing the DL data to the UE responsive to detecting one of the set of stop DL data events,
wherein the set of stop DL data events comprises a first stop DL data event of transmission of a sequence number (SN) status transfer message to the target base station and a second data event of receipt of a message from the target base station that a random access channel (RACH) procedure being performed by the UE.