Multi-user random access procedures for massive MIMO wireless communication systems

1. A method for performing multi-user random access procedures in a mobile telecommunications network between a base station and a user equipment (UE) having a plurality of antennas, the method comprising:

transmitting a random access signal set (RASS) message using one or more antennas of the plurality of UE antennas;

in response to receiving the RASS message:

transmitting, by the base station, a random access response physical downlink control channel (RAR-PDCCH) message; and

in response to receiving the RAR-PDCCH message:

transmitting a reciprocity reference signal set (RRSS) signal using the plurality of UE antennas.

2. The method of claim 1 , further comprising:

in response to receiving the RRSS signal:

transmitting, by the base station, a multi-user physical downlink control channel (MU-PDCCH) message.

3. The method of claim 1 ,

wherein the mobile telecommunications network includes a plurality of UE each having a plurality of antennas; and

wherein for each UE of the plurality of UE:

the UE performs a respective instance of said transmitting a RRSS signal using the plurality of UE antennas.

4. The method of claim 3 ,

wherein said transmitting the RRSS signal using the plurality of UE antennas is performed concurrently by the plurality of UE in a frequency domain interleaved manner.

5. The method of claim 1 ,

wherein the RASS message includes a random access radio network temporary identifier (RA-RNTI) selected by the UE.

6. The method of claim 1 , further comprising:

wherein the RRSS signal comprises a plurality of Zadoff-Chu (ZC) sequences transmitted by respective ones of the plurality of UE antennas.

7. The method of claim 6 ,

wherein each ZC sequence of the plurality of ZC sequences comprises a different cyclic shift for each antenna of the plurality of UE antennas.

8. The method of claim 6 ,

wherein each ZC sequence of the plurality of ZC sequences comprises a different ZC root sequence for each antenna of the plurality of UE antennas.

9. The method of claim 6 ,

wherein each ZC sequence of the plurality of ZC sequences comprises a different combination of cyclic shift and ZC root sequence for each antenna of the plurality of UE antennas.

10. The method of claim 1 , further comprising:

determining, by the base station, a number of the plurality of antennas of the UE from the received RASS message.

11. The method of claim 1 ,

wherein the RAR-PDCCH message is not multi-user precoded.

12. The method of claim 1 ,

wherein the RAR-PDCCH message includes information to indicate one or more of:

a desired uplink transmission rank;

uplink resources to be used for RRSS signaling by the UE;

coding sequences to be used for RRSS signaling by the UE; and

a random access radio network temporary identifier (RA-RNTI) received from the UE in the RASS message.

13. The method of claim 1 , further comprising:

wherein the RASS message comprises one or more Zadoff-Chu (ZC) sequences transmitted by respective ones of the one or more UE antennas.

14. The method of claim 1 ,

wherein the RRSS includes signaling to set up one or more of subsequent:

physical uplink shared channel (PUSCH) messaging; and

physical uplink control channel (PUCCH) messaging.

15. A user equipment (UE) that performs multi-user random access procedures with a base station in a mobile telecommunications network, the UE comprising:

a plurality of antennas; and

transmit/receive circuitry configured to:

transmit a random access signal set (RASS) message using one or more of the plurality of UE antennas;

receive, from the base station, a random access response physical downlink control channel (RAR-PDCCH) message; and

in response to receiving the RAR-PDCCH message:

transmit a reciprocity reference signal set (RRSS) signal using the plurality of UE antennas.

16. The UE of claim 15 ,

wherein the transmit/receive circuitry is further configured to:

receive, from the base station, a multi-user physical downlink control channel (MU-PDCCH) message.

17. The UE of claim 15 ,

wherein the transmit/receive circuitry transmits the RRSS signal in a frequency domain interleaved manner with a plurality of other UEs of the mobile telecommunications network each configured to concurrently transmit an RRSS signal.

18. The UE of claim 15 ,

wherein the RASS message includes a random access radio network temporary identifier (RA-RNTI) selected by the UE.

19. The UE of claim 15 ,

wherein the RRSS signal comprises a plurality of Zadoff-Chu (ZC) sequences transmitted by respective ones of the plurality of UE antennas; and

wherein each ZC sequence of the plurality of ZC sequences comprises an arrangement according to one of the following list:

each ZC sequence of the plurality of ZC sequences comprises a different cyclic shift for each antenna of the plurality of UE antennas;

each ZC sequence of the plurality of ZC sequences comprises a different ZC root sequence for each antenna of the plurality of UE antennas; and

each ZC sequence of the plurality of ZC sequences comprises a different combination of cyclic shift and ZC root sequence for each antenna of the plurality of UE antennas.

20. A base station that performs multi-user random access procedures with a user equipment (UE) having a plurality of antennas in a mobile telecommunications network, the base station comprising:

transmit/receive circuitry configured to:

receive a random access signal set (RASS) message from the UE transmitted by one or more antennas of the plurality of UE antennas;

in response to receiving the RASS message:

transmit a random access response physical downlink control channel (RAR-PDCCH) message; and

receive a reciprocity reference signal set (RRSS) signal from the UE transmitted by the plurality of UE antennas.

21. The base station of claim 20 ,

wherein the transmit/receive circuitry is further configured to, in response to receiving the RRSS signal:

transmit a multi-user physical downlink control channel (MU-PDCCH) message.

22. The base station of claim 20 ,

wherein the transmit/receive circuitry is configured to receive the RRSS signal from the UE in a frequency domain interleaved manner with a plurality of other UEs of the mobile telecommunications network that each concurrently transmit an RRSS signal.

23. The base station of claim 20 , further comprising:

a processor configured to determine a number of the plurality of antennas of the UE from the received RASS message.

24. The base station of claim 20 ,

wherein the RAR-PDCCH message is not multi-user precoded.