Method, apparatus and computer program to map a cyclic shift to a channel index
From the network perspective, an uplink resource allocation (PDCCH) is sent that grants an uplink resource to a plurality of user equipments UEs, and the allocation has an indication of a cyclic shift CS for each of the plurality of UEs. The granted uplink resource is mapped to a downlink resource (PHICH) in dependence on the indicated CS for each of the plurality of UEs. The mapping is such that for a predetermined number of UEs being allocated a same uplink resource in a single MU-MIMO uplink resource allocation grant, each pair of said predetermined number of UEs which map to an adjacent downlink resource exhibit an optimized CS relative to one another. The network sends to each of the respective plurality of UEs on the respective mapped downlink resource an indication (ACK/NACK) about data received (on a PUSCH). Apparatus, method, and computer programs for network and UE side implementations are detailed.
1. A method comprising:
receiving an uplink resource allocation in a wireless communications network and an indication in the granted uplink resource allocation of a cyclic shift;
sending data on the granted uplink resource;
mapping the granted uplink resource to a downlink resource in dependence on the indicated cyclic shift, such that user equipment-specific cyclic shifts mapped to adjacent downlink resources are non-adjacent cyclic shifts relative to one another; and
receiving on the mapped downlink resource an indication about the sent data; and
wherein the cyclic shift is for a demodulation reference signal and the indication of the cyclic shift is a dynamic cyclic shift indicator of three bits that indicates a user-specific cyclic shift.
2. The method of claim 1 , wherein:
the downlink resource comprises a physical hybrid-automatic repeat request indicator channel and mapping the granted uplink resource to the downlink resource in dependence on the indicated cyclic shift comprises mapping the granted uplink resource to an index of the indicator channel that is offset according to the indicated cyclic shift which is a demodulation reference signal cyclic shift index;
the mapping is according to a linear mapping rule stored in a local memory of a user equipment; and
the indication about the sent data is one of an acknowledgement and a negative acknowledgement.
3. The method of claim 2 , wherein a resource space for the mapped indicator channel is smaller than a signaling space for the indication of the cyclic shift.
4. A computer program product embodied on a non-transitory computer-readable medium storing a program of computer readable instructions that, when executed by a computer, is configured to provide instructions to control or carry out:
receiving an uplink resource allocation and an indication in the granted uplink resource allocation of a cyclic shift;
sending data on the granted uplink resource;
mapping the granted uplink resource to a downlink resource in dependence on the indicated cyclic shift, such that user equipment-specific cyclic shifts mapped to adjacent downlink resources are non-adjacent cyclic shifts relative to one another; and
receiving on the mapped downlink resource an indication about the sent data; and
wherein the cyclic shift is for a demodulation reference signal and the indication of the cyclic shift is a dynamic cyclic shift indicator of three bits that indicates a user-specific cyclic shift.
5. An apparatus comprising:
a receiver configured to receive an uplink resource allocation in a wireless communications network and an indication in the granted uplink resource allocation of a cyclic shift specific to a user equipment;
a transmitter configured to send data on the granted uplink resource;
a memory configured to store a mapping rule that maps the granted uplink resource to a downlink resource in dependence on the indicated cyclic shift,
wherein user equipment-specific cyclic shifts mapped to adjacent downlink resources are non-adjacent cyclic shifts relative to one another, and
wherein the receiver is further configured to receive on the mapped downlink resource an indication about the sent data; and
wherein the cyclic shift is for a demodulation reference signal and the indication of the cyclic shift is a dynamic cyclic shift indicator of three bits that indicates a user-specific cyclic shift.
6. The apparatus of claim 5 , wherein:
the downlink resource comprises a physical hybrid-automatic repeat request indicator channel and mapping the granted uplink resource to the downlink resource in dependence on the indicated cyclic shift comprises mapping the granted uplink resource to an index of the indicator channel that is offset according to the indicated cyclic shift which is a demodulation reference signal cyclic shift index;
the mapping is according to a linear mapping rule stored in a local memory of a user equipment; and
the indication about the sent data is one of an acknowledgement and a negative acknowledgement.
7. The apparatus of claim 6 , wherein a resource space for the mapped indicator channel is smaller than a signaling space for the indication of the cyclic shift.
8. A method comprising:
sending an uplink resource allocation in a wireless communications network and an indication in the granted uplink resource allocation of a cyclic shift specific to a user equipment;
mapping the granted uplink resource to a downlink resource in dependence on the indicated cyclic shift, such that user equipment-specific cyclic shifts mapped to adjacent downlink resources are non-adjacent user equipment-specific cyclic shifts relative to one another; and
sending on the mapped downlink resource an indication about data received; and
wherein the cyclic shift is a demodulation reference signal cyclic shift; and the indication of the cyclic shift is a dynamic cyclic shift indicator of three bits that indicates a relative cyclic shift in a cell.
9. The method of claim 8 , wherein:
the downlink resource comprises a physical hybrid-automatic repeat request indicator channel and mapping the granted uplink resource to the downlink resource in dependence on the indicated cyclic shift comprises mapping the granted uplink resource to an index of the indicator channel that is offset according to the indicated cyclic shift;
the mapping is according to a linear mapping rule stored in a local memory of an access node executing the method; and
the indication about the data received on the mapped downlink resource is one of an acknowledgement and a negative acknowledgement.
10. The method of claim 9 , wherein a resource space for the mapped indicator channel is smaller than a signaling space for the indication of the cyclic shift.
11. A computer program product embodied on a non-transitory computer-readable medium storing a program of computer readable instructions that, when executed by a computer, is configured to provide instructions to control or carry out:
sending an uplink resource allocation and an indication in the granted uplink resource allocation of a cyclic shift specific to a user equipment;
mapping the granted uplink resource to a downlink resource in dependence on the indicated cyclic shift, such that user equipment-specific cyclic shifts mapped to adjacent downlink resources are non-adjacent user equipment-specific cyclic shifts relative to one another; and
sending on the mapped downlink resource an indication about data received; and
wherein the cyclic shift is a demodulation reference signal cyclic shift; and the indication of the cyclic shift is a dynamic cyclic shift indicator of three bits that indicates a relative cyclic shift in a cell.
12. An apparatus comprising:
a transmitter configured to send an uplink resource allocation and an indication in the granted uplink resource allocation of a cyclic shift specific to a user equipment;
a memory that comprises a mapping of a granted uplink resource to a downlink resource in dependence on the indicated cyclic shift, such that user equipment-specific cyclic shifts mapped to adjacent downlink resources are non-adjacent user equipment-specific cyclic shifts relative to one another; and
the transmitter further configured to send on the mapped downlink resource an indication about data received; and
wherein the cyclic shift is a demodulation reference signal cyclic shift; and the indication of the cyclic shift is a dynamic cyclic shift indicator of three bits that indicates a relative cyclic shift in a cell; and
the apparatus further comprising a receiver configured to monitor the uplink resource that was granted.
13. The apparatus of claim 12 , wherein:
the downlink resource comprises a physical hybrid-automatic repeat request indicator channel and mapping the granted uplink resource to the downlink resource in dependence on the indicated cyclic shift comprises mapping the granted uplink resource to an index of the indicator channel that is offset according to the indicated cyclic shift which is a demodulation reference signal cyclic shift index for a user equipment;
the mapping is according to a linear mapping rule stored in the memory; and
the indication about the data received on the respective mapped downlink resource is one of an acknowledgement and a negative acknowledgement.
14. The apparatus of claim 13 , wherein a resource space for the mapped indicator channel is smaller than a signaling space for the indication of the cyclic shift.