Mobility handling in Ultra Dense Networks
User Equipment (UE) mobility in Ultra Dense Networks (UDNs) is based on communication signal layers, which could include respective data streams in an Orthogonal Frequency Division Multiplexing (OFDM) domain, a code domain using respective codebooks, and/or a spatial domain, for example. A UE uses candidate layer decoding parameters in applying layer-based decoding to communication signals that it received from network nodes. Layers could be allocated to UEs and transition between network nodes as UEs move between different network service areas. Layers could instead be allocated to network nodes. Layer-based decoding provides for UE mobility without requiring explicit handover processing every time a UE moves between different service areas.
1. A method performed by a user equipment (UE), the method comprising:
receiving a physical downlink control channel (PDCCH) based on spatial domain layer decoding parameters, the PDCCH identifying spatial domain layers in a communication network;
receiving a plurality of communication signals from a subset of network nodes in the communication network, each communication signal of the plurality of communication signals being associated with a respective one of the spatial domain layers in the communication network;
decoding the plurality of communication signals using the spatial domain layer decoding parameters;
transmitting, to the subset of network nodes, acknowledgement/negative acknowledgement (ACK/NAK) signaling comprising, for each respective spatial domain layer, an indication of which of the spatial domain layer decoding parameters were used to decode the communication signal associated with the respective spatial domain layer.
2. The method of claim 1 , further comprising receiving higher-level signaling comprising spatial domain layer decoding parameters for spatial domain layers that are allocated to the subset of network nodes in the communication network.
3. The method of claim 1 , wherein the decoding comprises decoding the plurality of communication signals using a Multiple Input Multiple Output (MIMO) decoder.
4. A non-transitory processor-readable medium storing instructions which, when executed by one or more processors of a user equipment (UE), cause the UE to:
receive a physical downlink control channel (PDCCH) based on spatial domain layer decoding parameters, the PDCCH identifying spatial domain layers in a communication network;
receive a plurality of communication signals from a subset of network nodes in the communication network, each communication signal of the plurality of communication signals being associated with a respective one of the spatial domain layers in the communication network;
decode the plurality of communication signals using the spatial domain layer decoding parameters;
transmit, to the subset of network nodes, acknowledgement/negative acknowledgement (ACK/NAK) signaling comprising, for each respective spatial domain layer, an indication of which of the spatial domain layer decoding parameters were used to decode the communication signal associated with the respective spatial domain layer.
5. The non-transitory processor-readable medium of claim 4 , comprising instructions, which when executed by the one or more processors of the UE, cause the UE to receive higher-level signaling comprising spatial domain layer decoding parameters for spatial domain layers that are allocated to the subset of network nodes in the communication network.
6. The non-transitory processor-readable medium of claim 4 , wherein the plurality of communication signals are decoded using a Multiple Input Multiple Output (MIMO) decoder.
7. A user equipment (UE) comprising:
a processor;
a memory storing instructions which, when executed by the processor causes the UE to:
receive a physical downlink control channel (PDCCH) based on spatial domain layer decoding parameters, the PDCCH identifying spatial domain layers in a communication network;
receive a plurality of communication signals from a subset of network nodes in the communication network, each communication signal of the plurality of communication signals being associated with a respective one of the spatial domain layers in the communication network;
decode the plurality of communication signals using the spatial domain layer decoding parameters;
transmit, to the subset of network nodes, acknowledgement/negative acknowledgement (ACK/NAK) signaling comprising, for each respective spatial domain layer, an indication of which of the spatial domain layer decoder parameters were used to decode the communication signal associated with the respective spatial domain layer.
8. The UE of claim 7 , wherein the memory stores instructions which, when executed by the processor, causes the UE to receive higher-level signal comprising spatial domain layer decoding parameters for spatial domain layers that are allocated to the subset of network nodes in the communication network.
9. The UE of claim 7 , wherein the plurality of communication signals are decoded using a Multiple Input Multiple Output (MIMO) decoder.