Dynamic uplink reuse in a C-RAN
This disclosure is directed to techniques for implementing uplink spatial reuse in a C-RAN.
1. A system to provide wireless service comprising:
a controller; and
a plurality of radio points;
wherein each of the radio points is associated with at least one antenna, wherein the plurality of radio points is communicatively coupled to the controller;
wherein the controller and the plurality of radio points are configured to implement at least a part of a base station in order to provide wireless service to a plurality of user equipment (UEs) using a cell;
wherein the controller is configured to implement a scheduler to schedule uplink transmissions from the UEs;
wherein the controller is configured to implement a combining receiver to receive uplink transmissions from each UE, the combining receiver configured to combine data indicative of the uplink transmissions from each UE as received at each radio point included in a combining zone assigned to that UE and communicated to the controller;
wherein the controller is configured to assign, to each UE, a respective minimum combining zone comprising a respective minimum subset of the radio points for use as the combining zone of the combining receiver for receiving uplink transmission from that UE;
wherein the controller is configured to assign, to each UE, a respective signal zone comprising a respective subset of the radio points suitable for inclusion in the combining zone of the combining receiver for receiving uplink transmission from that UE;
wherein the scheduler is configured to identify any groups of multiple UEs suitable for making respective uplink transmissions during a respective same time-and-frequency resource based on the respective minimum combining zones and signal zones assigned to the UEs and allocate time-and-frequency resources to the UEs using the minimum combining zones assigned to the UEs; and
wherein the scheduler is configured to, after allocating time-and-frequency resources to the UEs, attempt to expand the combining zones used for receiving uplink transmissions.
2. The system of claim 1 , wherein the controller is configured to assign to each UE a respective interference zone comprising a respective subset of the radio points that are not suitable for inclusion in the combining zone of the combining receiver for receiving uplink transmission from that UE.
3. The system of claim 2 , wherein the scheduler is configured to identify any groups of multiple UEs suitable for making respective uplink transmissions during the same time-and-frequency resource based on the respective minimum combining zones assigned to the UEs by:
determining if the minimum combining zone of a first UE does not include any radio points that are in the signal zone of a second UE and if the minimum combining zone of the second UE does not include any radio points that are in the signal zone of the first UE.
4. The system of claim 2 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for any group of multiple UEs that are scheduled to make respective uplink transmissions during the same time-and-frequency resource by expanding the combining zone of a first of the multiple UEs to include one or more additional radio points.
5. The system of claim 4 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for the multiple UEs by expanding the combining zone of the first of the multiple UEs to include any radio point in the minimum combining zone of a second of the multiple UEs that is in the signal zone of the first of the multiple UEs.
6. The system of claim 2 , wherein the controller is configured to assign the respective signal zone for each UE as a function of an ability of including each radio point in the respective combining zone of that UE to benefit the receiving of uplink transmissions from that UE.
7. The system of claim 1 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for a transmission time interval (TTI) by expanding the combining zone of one or more of the UEs if less than a total front-haul capacity for communicating data between the one or more radio points and the controller is not being used for the TTI.
8. The system of claim 1 , wherein the controller is communicatively coupled to the radio points using a switched ETHERNET network.
9. The system of claim 1 , wherein the uplink transmissions comprise Physical Uplink Shared Channel (PUSCH) transmissions.
10. The system of claim 1 , wherein the scheduler is configured to, for any group of multiple UEs that are scheduled to make respective uplink transmissions during the same time-and-frequency resource, assign respective UE-specific demodulation reference signal (DM-RS) cyclic shifts to the multiple UEs, each of the UE-specific DM-RS cyclic shifts having an associated distance between that UE-specific DM-RS cyclic shift and each of the other UE-specific DM-RS cyclic shifts, wherein the DM-RS cyclic shifts are assigned to maximize the respective distances.
11. The system of claim 1 , wherein the controller is configured to perform transmit power control for the uplink transmissions from the UEs using a closed-loop UE-specific target that is adapted for each UE based on a power headroom reported for that UE.
12. The system of claim 1 , wherein the controller is configured to perform transmit power control for the uplink transmissions from the UEs using a closed-loop UE-specific measured signal-to-interference-plus-noise ratio (SINR) that uses: a signal power measurement based on uplink transmissions from that UE; and
an interference-plus-noise measurement based on uplink transmissions from all scheduled UEs.
13. The system of claim 1 , wherein the controller is configured to perform transmit power control for a UE as a function of external interference caused by the uplink transmissions from that UE and of internal interference caused by uplink transmission from that UE.
14. The system of claim 1 , wherein the scheduler is configured to perform link adaptation for uplink transmissions from the UEs by selecting a modulation and coding scheme (MCS) for each UE based on a measured signal-to-interference-plus-noise ratio (SINR) for the UE and a sequence of acknowledgement and negative acknowledgement (ACK/NACK) messages associated with the uplink transmissions from the UE.
15. A system to provide wireless service comprising:
a controller; and
a plurality of radio points;
wherein each of the radio points is associated with at least one antenna, wherein the plurality of radio points is communicatively coupled to the controller;
wherein the controller and the plurality of radio points are configured to implement at least a part of a base station in order to provide wireless service to a plurality of user equipment (UEs) using a cell;
wherein the controller is configured to implement a scheduler to schedule uplink transmissions from the UEs;
wherein the scheduler is configured to identify any groups of multiple UEs suitable for making respective uplink transmissions during a respective same time-and-frequency resource, and, for any group of multiple UEs suitable for making respective uplink transmissions during the respective same time-and-frequency resource, schedule said multiple UEs to make respective uplink transmissions during the respective same time-and-frequency resource and assign respective UE-specific demodulation reference signal (DM-RS) cyclic shifts to said multiple UEs; and
wherein each of the UE-specific DM-RS cyclic shifts have an associated distance between that UE-specific DM-RS cyclic shift and each of the other UE-specific DM-RS cyclic shifts, wherein the DM-RS cyclic shifts are assigned to maximize the respective distances.
16. The system of claim 15 , wherein the controller is configured to implement a combining receiver to receive the uplink transmissions from each UE, the combining receiver configured to combine data indicative of the uplink transmissions from each UE as received at each radio point included in a combining zone assigned to that UE and communicated to the controller;
wherein the controller is configured to assign, to each UE, a respective minimum combining zone comprising a respective minimum subset of the radio points for use as the combining zone of the combining receiver for receiving uplink transmissions from that UE;
wherein the controller is configured to assign, to each UE, a respective signal zone comprising a respective subset of the radio points suitable for inclusion in the combining zone of the combining receiver for receiving uplink transmission from that UE;
wherein the scheduler is configured to identify any groups of multiple UEs suitable for making respective uplink transmissions during a respective same time-and-frequency resource based on the respective minimum combining zones and signal zones assigned to the UEs;
wherein the scheduler is configured to allocate time-and-frequency resources to the UEs using the minimum combining zones assigned to the UEs; and
wherein the scheduler is configured to, after allocating time-and-frequency resources to the UEs, attempt to expand the combining zones used for receiving uplink transmissions.
17. The system of claim 16 , wherein the controller is configured to assign to each UE a respective interference zone comprising a respective subset of the radio points that are not suitable for inclusion in the combining zone of the combining receiver for receiving uplink transmission from that UE.
18. The system of claim 17 , wherein the scheduler is configured to identify any groups of multiple UEs suitable for making respective uplink transmissions during the same time-and-frequency resource based on the respective minimum combining zones assigned to the UEs by:
determining if the minimum combining zone of a first UE does not include any radio points that are in the signal zone of a second UE and if the minimum combining zone of the second UE does not include any radio points that are in the signal zone of the first UE.
19. The system of claim 17 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for any group of multiple UEs that are scheduled to make respective uplink transmissions during the same time-and-frequency resource by expanding the combining zone of a first of the multiple UEs to include one or more additional radio points.
20. The system of claim 19 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for the multiple UEs by expanding the combining zone of the first of the multiple UEs to include any radio point in the minimum combining zone of a second of the multiple UEs that is in the signal zone of the first of the multiple UEs.
21. The system of claim 17 , wherein the controller is configured to assign the respective signal zone for each UE as a function of an ability of including each radio point in the respective combining zone of that UE to benefit the receiving of uplink transmissions from that UE.
22. The system of claim 16 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for a transmission time interval (TTI) by expanding the combining zone of one or more of the UEs if less than a total front-haul capacity for communicating data between the one or more radio points and the controller is not being used for the TTI.
23. The system of claim 15 , wherein the controller is communicatively coupled to the radio points using a switched ETHERNET network.
24. The system of claim 15 , wherein the uplink transmissions comprise Physical Uplink Shared Channel (PUSCH) transmissions.
25. The system of claim 15 , wherein the controller is configured to perform transmit power control for the uplink transmissions from the UEs using a closed-loop UE-specific target signal-to-interference-plus-noise ratio (SINR) that is adapted for each UE based on a power headroom reported for that UE.
26. The system of claim 15 , wherein the controller is configured to perform transmit power control for the uplink transmissions from the UEs using a closed-loop UE-specific measured signal-to-interference-plus-noise ratio (SINK) that uses: a signal power measurement based on uplink transmissions from that UE; and
an interference-plus-noise measurement based on uplink transmissions from all scheduled UEs.
27. The system of claim 15 , wherein the controller is configured to perform transmit power control for a UE as a function of external interference caused by the uplink transmissions from that UE and of internal interference caused by uplink transmission from that UE.
28. The system of claim 15 , wherein the scheduler is configured to perform link adaptation for uplink transmissions from the UEs by selecting a modulation and coding scheme (MCS) for each UE based on a measured signal-to-interference-plus-noise ratio (SINR) for the UE and a sequence of acknowledgement and negative acknowledgement (ACK/NACK) messages associated with the uplink transmissions from the UE.
29. A system to provide wireless service comprising:
a controller; and
a plurality of radio points;
wherein each of the radio points is associated with at least one antenna, wherein the plurality of radio points is communicatively coupled to the controller;
wherein the controller and the plurality of radio points are configured to implement at least a part of a base station in order to provide wireless service to a plurality of user equipment (UEs) using a cell;
wherein the controller is configured to implement a scheduler to schedule uplink transmissions from the UEs;
wherein the scheduler is configured to identify any groups of multiple UEs suitable for making respective uplink transmissions during a respective same time-and-frequency resource, and, for any multiple UEs that are able to make respective uplink transmissions during the respective same time-and-frequency resource, schedule said multiple UEs to make respective uplink transmissions during the respective same time-and-frequency resource; and
wherein the controller is configured to perform transmit power control for the uplink transmissions from the UEs using at least one of the following:
a closed-loop UE-specific target signal-to-interference-plus-noise ratio (SINR) that is adapted for each UE based on a power headroom reported for that UE; and
a closed-loop UE-specific measured SINR that uses: a signal power measurement based on uplink transmissions from that UE, and an interference-plus-noise measurement based on uplink transmissions from all scheduled UEs.
30. The system of claim 29 , wherein the controller is configured to perform transmit power control for a UE as a function of external interference caused by the uplink transmissions from that UE and of internal interference caused by uplink transmission from that UE.
31. The system of claim 29 , wherein the controller is configured to implement a combining receiver to receive the uplink transmissions from each UE, the combining receiver configured to combine data indicative of the uplink transmissions from each UE as received at each radio point included in a combining zone assigned to that UE and communicated to the controller;
wherein the controller is configured to assign, to each UE, a respective minimum combining zone comprising a respective minimum subset of the radio points for use as the combining zone of the combining receiver for receiving uplink transmission from that UE;
wherein the controller is configured to assign, to each UE, a respective signal zone comprising a respective subset of the radio points suitable for inclusion in the combining zone of the combining receiver for receiving uplink transmission from that UE;
wherein the scheduler is configured to identify any groups of multiple UEs suitable for making respective uplink transmissions during a respective same time-and-frequency resource based on the respective minimum combining zones and signal zones assigned to the UEs;
wherein the scheduler is configured to allocate time-and-frequency resources to the UEs using the minimum combining zones assigned to the UEs; and
wherein the scheduler is configured to, after allocating time-and-frequency resources to the UEs, attempt to expand the combining zones used for receiving uplink transmissions.
32. The system of claim 31 , wherein the controller is configured to assign to each UE a respective interference zone comprising a respective subset of the radio points that are not suitable for inclusion in the combining zone of the combining receiver for receiving uplink transmission from that UE.
33. The system of claim 32 , wherein the scheduler is configured to identify any groups of multiple UEs suitable for making respective uplink transmissions during the same time-and-frequency resource based on the respective minimum combining zones assigned to the UEs by:
determining if the minimum combining zone of a first UE does not include any radio points that are in the signal zone of a second UE and if the minimum combining zone of the second UE does not include any radio points that are in the signal zone of the first UE.
34. The system of claim 32 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for any groups of multiple UEs that are scheduled to make respective uplink transmissions during the same time-and-frequency resource by expanding the combining zone of a first of the multiple UEs to include one or more additional radio points.
35. The system of claim 34 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for the multiple UEs by expanding the combining zone of the first of the multiple UEs to include any radio point in the minimum combining zone of a second of the multiple UEs.
36. The system of claim 32 , wherein the controller is configured to assign the respective signal zone for each UE as a function of an ability of including each radio point in the respective combining zone of that UE to benefit the receiving of uplink transmissions from that UE.
37. The system of claim 31 , wherein the scheduler is configured to attempt to expand the combining zones used for receiving uplink transmissions for a transmission time interval (TTI) by expanding the combining zone of one or more of the UEs if less than a total front-haul capacity for communicating data between the one or more radio points and the controller is not being used for the TTI.
38. The system of claim 29 , wherein the controller is communicatively coupled to the radio points using a switched ETHERNET network.
39. The system of claim 29 , wherein the uplink transmissions comprise Physical Uplink Shared Channel (PUSCH) transmissions.
40. The system of claim 29 , wherein the scheduler is configured to, for any group of multiple UEs that are scheduled to make respective uplink transmissions during the same time-and-frequency resource, assign respective UE-specific demodulation reference signal (DM-RS) cyclic shifts to the multiple UEs, each of the UE-specific DM-RS cyclic shifts having an associated distance between that UE-specific DM-RS cyclic shift and each of the other UE-specific DM-RS cyclic shifts, wherein the DM-RS cyclic shifts are assigned to maximize the respective distances.
41. The system of claim 29 , wherein the scheduler is configured to perform link adaptation for uplink transmissions from the UEs by selecting a modulation and coding scheme (MCS) for each UE based on a measured signal-to-interference-plus-noise ratio (SINR) for the UE and a sequence of acknowledgement and negative acknowledgement (ACK/NACK) messages associated with the uplink transmissions from the UE.
42. A system to provide wireless service comprising:
a controller; and
a plurality of radio points;
wherein each of the radio points is associated with at least one antenna, wherein the plurality of radio points is communicatively coupled to the controller;
wherein the controller and the plurality of radio points are configured to implement at least a part of a base station in order to provide wireless service to a plurality of user equipment (UEs) using a cell;
wherein the controller is configured to implement a scheduler to schedule uplink transmissions from the UEs;
wherein the scheduler is configured to perform link adaptation for uplink transmissions from the UEs by selecting a modulation and coding scheme (MCS) for each UE based on a measured signal-to-interference-plus-noise ratio (SINR) for the UE and a sequence of acknowledgement and negative acknowledgement (ACK/NACK) messages associated with the uplink transmissions from the UE.
43. The system of claim 42 , wherein selecting the MCS for each UE based on the SINR for the UE and the sequence of ACK/NACK messages associated with the uplink transmissions from the UE comprises:
determining an average modified SINR for each UE;
determining an augmented average SINR for each UE by applying an adaptation loop variable for the UE to the average modified SINR for the UE; and
selecting the MCS for each UE based on the determined augmented average SINR for the UE.
44. The system of claim 1 , wherein the combining receiver comprises an interference-rejection combining (IRC) receiver.
45. The system of claim 16 , wherein the combining receiver comprises an interference-rejection combining (IRC) receiver.
46. The system of claim 31 , wherein the combining receiver comprises an interference-rejection combining (IRC) receiver.
47. The system of claim 1 , wherein each of the radio points is remotely located from the controller.
48. The system of claim 15 , wherein each of the radio points is remotely located from the controller.
49. The system of claim 29 , wherein each of the radio points is remotely located from the controller.
50. The system of claim 42 , wherein each of the radio points is remotely located from the controller.