Accurate uplink power control for CoMP and C-RAN

1. A user equipment (UE) arranged to communicate with an enhanced Node B (eNB) that includes a set including multiple reception points (RPs), the UE comprising:

a transceiver configured to,

send an uplink power reference signal to the multiple reception points (RPs) of the set of RPs;

receive from the eNB, identification of a subset of the set that includes multiple RPs, the subset including two or more RPs from the set of RPs, and identification of a downlink reference signal power level for each reference signal to be used by an RP of the identified subset;

receive downlink reference signals from RPs of the identified subset; and

a processor configured to,

determine a path loss estimate for each received downlink reference signal received from an identified RP of the identified subset, based at least in part upon the downlink reference signal power level identified for the RP from which the reference signal is received; and

determine an uplink power level that is a function of the path loss estimates determined for the downlink signals received from the RPs of the identified subset;

wherein the transceiver and the processor are further configured to,

use the determined uplink power level during communication with the identified RPs.

2. The UE of claim 1 wherein the processor is further arranged to,

determine an overall path loss estimate as a function of the determined path loss estimates for each received downlink reference signal; and

wherein the determined uplink power level is a function of the determined overall path loss estimate.

3. The UE of claim 1 ,

wherein determining a path loss estimate for each received downlink reference signal includes determining a received signal received power (RSRP) for each such received downlink reference signal.

4. The UE of claim 1 ,

wherein determining a path loss estimate for each received downlink reference signal includes:

determining a received signal received power (RSRP) each such received downlink reference signal, and

determining a difference between the identified downlink reference signal power level and each determined RSRP.

5. The UE of claim 1 ,

wherein determining a path loss estimate for each received downlink reference signal includes:

determining a received signal received power (RSRP) for each such received downlink reference signal,

low pass filtering the determined RSRPs, and

determining a difference between the identified downlink reference signal power level and each determined low pass filtered RSRP.

6. The UE of claim 1 wherein the transceiver is further arranged to, receive identification of a type of downlink reference signal used for downlink path loss measurement.

7. The UE of claim 1 ,

wherein the downlink reference signal includes an eNB downlink cell reference signal.

8. The UE of claim 1 wherein the transceiver is further arranged to,

transmit and receive messages using orthogonal frequency-division multiplexing during message communication with the RPs in accordance with a 3GPP Long Term Evolution (LTE) Advanced (LTE-A) standard.

9. The UE of claim 1 including further including:

one or more antennas arranged to communicate with the eNB;

a storage device encoded to store,

instruction code to cause the processor to use the transmitter to send an uplink power reference signal to the subset of multiple RPs;

indicia of the subset including two or RPs identified by the eNB;

indicia of the downlink reference signal power level for each reference signal identified by the eNB;

instruction code to cause the processor to determine a path loss estimate for each downlink reference signal received by the receiver circuitry from an RP of the identified subset, based at least in art upon the downlink reference signal power level identified for the RP from which the reference signal is received;

instruction code to cause the processor to determine an uplink power level that is a function of the path loss estimates determined for the downlink signals received from the RPs of the identified subset; and

instruction code to cause the processor to use the determined uplink power level during communication with the identified RPs.

10. The UE of claim 9 ,

wherein the instruction code to cause the processor to determine a path loss estimate each received downlink reference signal includes:

instruction code to cause the processor to determine a received signal received power (RSRP) for each such received downlink reference signal, and

instruction code to cause the processor to determine for each received downlink reference signal a difference between its identified downlink reference signal power level and its determined RSRP.

11. The UE of claim 10 further including:

instruction code to cause the processor to determine an overall path loss estimate as a function of the determined path loss estimates for each received downlink reference signal;

wherein the determined uplink power level is a function of the determined overall path loss estimate.

12. A method of communication between a user equipment (UE) and an enhanced node B (eNB) that includes a plurality reception points (RPs) arranged to implement joint processing of signals received by multiple reception points (RPs) associated with the eNB, the method comprising:

sending an uplink power reference by the UE to multiple RPs of the eNB;

receiving from the eNB by the UE from the eNB identification of a subset including two or more RPs associated with the eNh and identification of a downlink reference signal power level for each reference signal to be used by an RP of the identified subset;

receiving a downlink reference signal by the UE from each of the RPs of the identified subset; and

transmit to the identified RPs, by the UE, messages having an uplink power level that is a function of received signal received powers (RSRPs) of the identified downlink reference signals received by the UE.

13. The method of claim 12 further includes the UE,

determining a path loss estimate for each received downlink reference signal received from an identified RP, based at least in part upon the downlink reference signal power level identified for the RP from which the reference signal is received; and

determining an overall path loss estimate as a function of the determined path loss estimates for each received downlink reference signal;

wherein the uplink power level is a function of the determined overall path loss estimate.

14. The method of claim 12 further includes the UE,

determining a power loss as a function of the identified downlink reference signal power level for each received downlink reference signal; and

determining the uplink power level as a function of the determined power losses.

15. The method of claim 12 further includes the UE,

determining a received signal received power (RSRP) for each such received downlink reference signal;

low pass filtering the determined RSRPs;

determining for each received downlink reference signal a difference between its identified downlink reference signal power level and its determined low pass filtered RSRP; and

determining the uplink power level as a function of the determined differences.

16. The method of claim 12 further includes the UE,

transmit and receive messages using orthogonal frequency-division multiplexing during message communication with the RPs in accordance with a 3GPP Long Term Evolution (LTE) Advanced (LTE-A) standard.

17. An enhanced Node B (eNB) that includes a base station and a plurality reception points (RPs) arranged to implement joint processing of signals received by multiple reception points (RPs) associated with the eNB,

wherein the multiple RPs of the eNB are arranged to receive an uplink power reference signal transmitted by a user equipment (UE);

wherein the base station is arranged to determine a subset including two or more RPs as a function of the received signal received power (RSRP) of the uplink power reference signal received by the RPs and to determine a reference signal power level for each RP of the subset including two or ore RPs;

wherein the base station configures at least one RP to send to the UE identification of the subset including two or more RPs and identification of a downlink reference signal power level for each reference signal for each RP of the subset of RPs; and

wherein the base station configures each RP of the subset including two or more RPs to send a downlink reference signal to the UE.

18. The eNB of claim 17 further arranged to,

transmit and receive messages using orthogonal frequency-division multiplexing during message communication with the UE in accordance with a 3GPP Long Term Evolution (LTE) Advanced (LTE-A) standard.

19. The eNB of claim 17 ,

wherein the subset including two or more RPs includes the RPs having largest magnitude RSRPs of the uplink power reference signal.

20. A method of communication between a user equipment (UE) and an enhanced Node B (eNB) that includes a plurality reception points (RPs) arranged to implement joint processing of signals received by multiple reception points (RPs) associated with the eNB comprising:

receiving by a plurality of RPs within the access point an uplink power reference signal transmitted by the UE;

determining by the eNB a subset including two or more RPs as a function of the received signal received power (RSRP) of the uplink power reference signal received by the respective RPs and a reference signal power level for each RP of the subset including two or more RPs;

sending by the eNB to the UE identification of the subset including two or more RPs and identification of a downlink reference signal power level for each reference signal for each RP of the subset including two or more RPs; and

sending by the RPs of the subset the downlink a reference signal to the UE.

21. The method of claim 20 ,

wherein determining the subset including two or more RPs as a function of the RSRP of the uplink power reference signal received by the respective RPs includes selecting RPs with the strongest RSRPs for membership in the subset including two or more RPs.

22. The method of claim 20 further including:

jointly processing by the access point signals received by RPs of the subset including two or more RPs from the UE,

transmitting to the identified RPs, by the UE, messages having an uplink power level that is a function of received signal received powers (RSRPs) of the identified downlink reference signals received by the UE.

23. The method of claim 20 further including:

sending by the eNB identification of a type of downlink reference signal used for downlink path loss measurement.

24. The method of claim 20 further including:

transmit and receive messages using orthogonal frequency-division multiplexing by the RPs during message communication with the UE in accordance with a 3GPP Long Term Evolution (LTE) Advanced (LTE-A) standard.