Methods and apparatuses for signaling and determining reference signal offsets
Methods and apparatuses disclosed herein enable the use of Demodulation Reference Signal, DMRS, sequences that are numbered relative to an overall system bandwidth ( 30 ), while simultaneously enabling wireless communication devices ( 12 ) to determine the DRMS sequence elements mapped to their scheduled bandwidths ( 36 ) within the system bandwidth ( 30 ). Advantageously, the wireless communication devices ( 12 ) need not know the system bandwidth ( 30 ), or even be aware of where their scheduled bandwidths ( 36 ) reside within the system bandwidth ( 30 ).
1. A method of operation at a wireless communication device configured for operation in a wireless communication network, the method comprising:
determining, based on information received via a downlink transmission from a radio network node of the network, a sequence offset for a reference signal sequence;
determining, based on the sequence offset, which portion of the reference signal sequence overlays a scheduled bandwidth of the wireless communication device, referred to as an overlaying portion of the reference signal sequence; and
transmitting, as an uplink transmission, one or more of the sequence elements contained in the overlaying portion of the reference signal sequence;
wherein the scheduled bandwidth is a portion of a larger, system bandwidth associated with the network, and wherein the reference signal sequence overlays the system bandwidth according to a defined mapping between respective sequence elements constituting the reference signal sequence and respective subcarriers constituting the system bandwidth.
2. The method of claim 1 , wherein the information received from the network directly or indirectly indicates a position of a configured bandwidth within the system bandwidth, and wherein determining the sequence offset comprises determining the sequence offset based on the position of the configured bandwidth and a position of the scheduled bandwidth within the configured bandwidth.
3. The method of claim 1 , wherein the information received from the network indicates a seed value, and wherein determining the sequence offset comprises implicitly determining the sequence offset by using the seed value to seed a sequence element generation function, wherein the seed value is a function of the sequence offset.
4. The method of claim 3 , wherein the sequence element generation function, as seeded by the seed value, generates sequence elements corresponding to a configured bandwidth of the wireless communication device, which configured bandwidth contains the scheduled bandwidth, and wherein the method includes determining the overlaying portion of the reference signal sequence, based on a position of the scheduled bandwidth within the configured bandwidth.
5. The method of claim 1 , wherein the defined mapping maps respective sequence elements constituting the reference signal sequence to respective subcarriers constituting the system bandwidth.
6. The method of claim 1 , wherein the information received from the network indicates an offset relating a position of a configured bandwidth of the wireless communication device to a reference position within the system bandwidth, and wherein determining the sequence offset comprises determining the sequence offset based on the position of the configured bandwidth in relation to the reference position, and further based on a position of the scheduled bandwidth within the configured bandwidth.
7. A wireless communication device configured for operation in a wireless communication network and comprising:
communication circuitry configured for wirelessly communicating with one or more nodes in the network; and
processing circuitry operatively associated with the communication circuitry and configured to:
determine, based on information received via a downlink transmission from a radio network node of the network, a sequence offset for a reference signal sequence;
determine, based on the sequence offset, which portion of the reference signal sequence overlays a scheduled bandwidth of the wireless communication device, referred to as an overlaying portion of the reference signal sequence; and
transmit, as an uplink transmission, one or more of the sequence elements contained in the overlaying portion of the reference signal sequence;
wherein the scheduled bandwidth is a portion of a larger, system bandwidth associated with the network, and wherein the reference signal sequence overlays the system bandwidth according to a defined mapping between respective sequence elements constituting the reference signal sequence and respective subcarriers constituting the system bandwidth.
8. The wireless communication device of claim 7 , wherein the information received from the network directly or indirectly indicates a position of a configured bandwidth within the system bandwidth, and wherein the processing circuitry is configured to determine the sequence offset based on the position of the configured bandwidth and a position of the scheduled bandwidth within the configured bandwidth.
9. The wireless communication device of claim 7 , wherein the information received from the network indicates a seed value, and wherein the processing circuitry is configured to determine the sequence offset implicitly, by using the seed value to seed a sequence element generation function, wherein the seed value is a function of the sequence offset.
10. The wireless communication device of claim 9 , wherein the sequence element generation function, as seeded by the seed value, generates sequence elements corresponding to a configured bandwidth of the wireless communication device, which configured bandwidth contains the scheduled bandwidth, and wherein the processing circuitry is configured to determine the overlaying portion of the reference signal sequence, based on a position of the scheduled bandwidth within the configured bandwidth.
11. The wireless communication device of claim 7 , wherein the defined mapping maps respective sequence elements constituting the reference signal sequence to respective subcarriers constituting the system bandwidth.
12. The wireless communication device of claim 7 , wherein the information received from the network indicates an offset relating a position of a configured bandwidth of the wireless communication device to a reference position within the system bandwidth, and wherein the processing circuitry is configured to determine the sequence offset based on the position of the configured bandwidth in relation to the reference position, and further based on a position of the scheduled bandwidth within the configured bandwidth.