Cloud Radio Access Network

• US 20150244430A1
• Filed: 05/12/2015
• Published: 08/27/2015
• Est. Priority Date: 04/26/2001
• Status: Active Grant

• Current Assignee: Genghiscomm Holdings, LLC
• Original Assignee: Genghiscomm Holdings, LLC
• Inventors: Shattil, Steve
• Granted Patent: US 9,893,774 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04J 11/003 at the transmitter transmission to multiple receive units in multiple input multiple output [MIMO] H04B7/0452; transmit antenna weighting H04B7/0615
• CPC Class Codes: H04L 41/0816 the condition being an adaptation, e.g. in response to network events
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements

Abstract

Instead of just consuming network resources, client devices create network resources via cooperative subspace processing to increase data bandwidth and expand radio coverage so the network grows dynamically with demand. Server-side cooperative-MIMO provides joint processing for geographically distributed base stations with overlapping coverage areas. A combination of centralized coordination and distributed computing pools and virtualizes base station processing, which reduces complexity, size, and power requirements of base stations to facilitate rapid and inexpensive network deployments. Cooperative subspace coding reduces overhead and transport-layer inefficiencies, and enables each channel to simultaneously employ multiple network paths, even over non-homogeneous networks. Cooperative subspace processing enables a client in a first network to reuse its allocated channels for communicating in another network without interfering with the first network.

Claims

1. A radio access network (RAN), comprising:

a plurality of geographically distributed base transceiver stations configured to serve a plurality of user equipments (UEs);

a centralized baseband processing pool communicatively coupled to the plurality of geographically distributed base transceiver stations by a fronthaul network, the centralized baseband processing pool comprising a data center cloud configured to employ real-time virtualization of RAN base stations, wherein RAN base station baseband processing is implemented via distributed computing.

2. The RAN recited in claim 1, wherein multiple ones of the plurality of geographically distributed base transceiver stations are configured to produce overlapping coverage areas, and the centralized baseband processing pool is configured to perform spatial multiplexing, wherein the RAN base station baseband processing comprises at least one of subspace coding and subspace decoding across at least one plurality of antennas comprising antennas on the multiple ones of the plurality of geographically distributed base transceiver stations.

3. The RAN recited in claim 2, wherein the at least one of subspace coding and subspace decoding is configured to perform at least one of a set of algorithms, the set comprising maximum ratio, minimum mean square error, zero forcing, and successive interference cancellation algorithms.

4. The RAN recited in claim 1, wherein at least one of a set, the set comprising the centralized baseband processing pool and the plurality of geographically distributed base transceiver stations, is configured to perform channel estimation in the RAN from at least one of measurements of received pilot signals, measurements of received training sequences, a blind technique that jointly estimates channels and payload data, a channel measurement technique that employs open-loop feedback, a channel measurement technique that employs closed-loop feedback, and a channel estimation technique that includes reciprocity calibration of RF front-end hardware.

5. The RAN recited in claim 1, wherein the virtualization of RAN base stations is implemented on a software-defined radio platform that generates a plurality of virtual RAN base stations.

6. The RAN recited in claim 1, wherein the plurality of geographically distributed base transceiver stations comprise remote radio heads configured to perform radio frequency (RF) front-end processing in the RAN, comprising at least one of RF signal amplification, frequency conversion, digital-to-analog conversion, and analog-to-digital conversion.

7. The RAN recited in claim 1, wherein the centralized baseband processing pool is configured to perform at least one of waveform shaping, error detection, error correction, power control, channel selection, multiple access control, multiplexing, modulation, formatting, synchronization, coding, RAN resource allocation, and load balancing.

8. In a radio access network (RAN) comprising a plurality of geographically distributed base transceiver stations, a method comprising:

centralizing RAN baseband-processing for the plurality of base transceiver stations in a central processing facility communicatively coupled to the plurality of geographically distributed base transceiver stations by a fronthaul network;

virtualizing the RAN baseband processing; and

distributing virtualized RAN baseband processing across a plurality of processors configured to work together.

9. The method recited in claim 8, wherein multiple ones of the plurality of geographically distributed base transceiver stations are configured to produce overlapping coverage areas, and the virtualized RAN baseband processing comprises at least one of subspace coding and subspace decoding across at least one plurality of antennas comprising antennas on multiple ones of the plurality of geographically distributed base transceiver stations.

10. The method recited in claim 9, wherein the at least one of subspace coding and subspace decoding comprises at least one of a set of algorithms, the set comprising maximum ratio, minimum mean square error, zero forcing, and successive interference cancellation algorithms.

11. The method recited in claim 8, further comprising deriving channel estimates in the RAN from at least one of measuring a pilot signal in a received transmission, measuring a training sequence in a received transmission, a blind channel estimation technique that jointly estimates channels and payload data, a channel measurement technique that employs open-loop feedback, a channel measurement technique that employs closed-loop feedback, and a channel estimation technique that includes reciprocity calibration of RF front-end hardware.

12. The method recited in claim 8, wherein virtualizing the RAN baseband processing comprises employing a software-defined radio platform that generates a plurality of virtual RAN base stations.

13. The method recited in claim 8, wherein the virtualized RAN baseband processing comprises at least one of waveform shaping, error detection, error correction, power control, channel selection, multiple access control, multiplexing, modulation, formatting, synchronization, coding, RAN resource allocation, and load balancing.

14. The method recited in claim 8, wherein virtualizing the RAN baseband processing is configured to adapt the RAN baseband processing to changing RAN configurations, including at least one of when a base transceiver station joins the RAN, when a base transceiver station leaves the RAN, and when a geographic location of a base transceiver station changes.

15. A data center cloud configured to perform the method recited in claim 8.

16. A non-transitory computer readable storage medium having computer readable code thereon, the medium comprising instructions to:

pool radio access network (RAN) baseband processing for a plurality of geographically distributed base transceiver stations;

virtualize the RAN baseband processing; and

distribute virtualized RAN baseband processing operations over a plurality of processors configured to work together.

17. The medium recited in claim 16, wherein multiple ones of the plurality of geographically distributed base transceiver stations have overlapping coverage areas, and the RAN baseband processing comprises at least one of subspace pre-coding and subspace decoding across at least one plurality of antennas comprising antennas on multiple ones of the plurality of geographically distributed base transceiver stations.

18. The medium recited in claim 17, wherein the at least one of subspace coding and subspace decoding comprises at least one of a set of algorithms, the set comprising maximum ratio, minimum mean square error, zero forcing, and successive interference cancellation algorithms.

19. The medium recited in claim 17, wherein the at least one of subspace coding and subspace decoding employs RAN channel state information determined from at least one of measuring a pilot signal in a received transmission, measuring a training sequence in a received transmission, a blind channel estimation technique that jointly estimates channels and payload data, a channel measurement technique that employs open-loop feedback, a channel measurement technique that employs closed-loop feedback, and a channel estimation technique that includes reciprocity calibration of RF front-end hardware.

20. The medium recited in claim 16, wherein the virtualized RAN baseband processing operations are implemented on a software-defined radio platform that generates a plurality of virtual RAN base stations.

21. The medium recited in claim 16, wherein the virtualized RAN baseband processing comprises at least one of waveform shaping, error detection, error correction, power control, channel selection, multiple access control, multiplexing, modulation, formatting, synchronization, coding, RAN resource allocation, and load balancing.

22. The medium recited in claim 16, further comprising instructions to adapt the virtualized RAN baseband processing to changing RAN configurations, including at least one of when a base transceiver station joins the RAN, when a base transceiver station leaves the RAN, and when a geographic location of a base transceiver station changes.

23. The medium recited in claim 16, further comprising instructions to:

select a plurality of antennas residing on multiple ones of the plurality of geographically distributed base transceiver stations to serve each of a plurality of user equipments (UEs);

from each UE'"'"'s channel state information, calculate subspace processing weights for the each UE'"'"'s corresponding plurality of antennas;

using a fronthaul network communicatively coupled to the plurality of geographically distributed base transceiver stations, coordinate the each UE'"'"'s corresponding plurality of antennas to communicate in the RAN; and

perform at least one of subspace multiplexing of RAN signals transmitted by the plurality of antennas and subspace demultiplexing of RAN signals received by the plurality of antennas to enable multiple UEs to employ concurrent interference-free same-band communications.