Method of cooperative MIMO wireless communication and base station using the same

• US 9,337,973 B2
• Filed: 09/03/2013
• Issued: 05/10/2016
• Est. Priority Date: 09/11/2012
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Hou, Hsin-An, Lin, Wan-Yi, Chen, Yung-Han
• Primary Examiner(s): Choudhry, Samina
• Application Number:
  US14/016,245
• Publication Number:
  US 20140071912A1
• Time in Patent Office: 980 Days
• Field of Search: 370/329
• US Class Current: 1/1
• 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: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation

Abstract

The present disclosure proposes a method of cooperative MIMO wireless communication, and a base station using the same. A base station would have a plurality of radio remote units (RRUs), and each of the RRUs may have a specific radio coverage and a plurality of antennas coupled to each of the RRUs. The function of the base station may include receiving a UE information, receiving a service flow, deriving a service type of the service flow, and determining a MIMO scheme, modulating the service flow into a MIMO stream according to the MIMO scheme, allocating a plurality of resource blocks, wherein the resource blocks may correspond to a portion or all of the RRUs, distributing the MIMO stream into a plurality of downlink sub streams and transmitting the downlink sub streams through the resource blocks by the RRUs corresponding to the resource blocks.

Claims

1. A method of cooperative multiple-input-multiple-output (MIMO) wireless communication, configured for a base station with a plurality of radio remote units (RRUs), wherein each of the RRUs respectively has a radio coverage and a plurality of antennas are coupled to each of the RRUs, wherein the RRUs locate on different geographical locations, the method comprising:

receiving an user equipment (UE) information comprising a location of the UE;

receiving a service flow from an application layer service provider;

deriving a service type of the service flow, wherein the service type comprises a broadcast service type, a multicast service type, and a unicast service type;

determining a MIMO scheme for modulating the service flow into a MIMO stream for the UE according to the service type and the UE information, wherein if the location of the UE is in an area within the radio coverage of at least two of the RRUs, the MIMO scheme of the UE is determined to be a site MIMO scheme performed by the at least two of the RRUs, wherein the MIMO scheme comprises an antenna scheme, or a combination of the antenna scheme and a site diversity scheme, wherein the antenna scheme comprises an antenna multiplexing scheme and an antenna diversity scheme;

allocating a plurality of resource blocks to part or all of the RRUs according to the MIMO scheme, the UE information and the service type,

modulating the service flow into the MIMO stream according to the MIMO scheme; and

distributing the MIMO stream into a plurality of downlink sub streams and transmitting the downlink sub streams through the resource blocks by the part or all of the RRUs, wherein the at least two of the RRUs cooperatively transmit the downlink sub streams for the UE according to the site MIMO scheme.

2. The method according to claim 1, wherein the step of determining the MIMO scheme further comprising:

detecting the UE corresponding to the service flow;

estimating a location of the UE; and

associating the UE with one or more RRUs according to the UE information.

3. The method according to claim 1, wherein in receiving phase, the method further comprising:

collecting a plurality of uplink sub streams through the resource blocks by part or all of the RRUs which are corresponding to the resource blocks; and

demodulating the service flow out of uplink sub streams according to the MIMO scheme.

4. The method according to claim 2, wherein:

the MIMO scheme comprising an antenna scheme, or a combination of the antenna scheme and a site diversity scheme, wherein the antenna scheme comprising an antenna multiplexing scheme and an antenna diversity scheme.

5. The method according to claim 4, wherein the UE information comprises one or multiple parameters of signal strength, signal to interference ratio, round trip time, UE location and UE identifier.

6. The method according to claim 5, wherein the step of allocating one or multiple resource blocks further comprising:

allocating one or multiple resource blocks sequentially according to the MIMO scheme, the service type, the location of the UE and the RRUs associated with the UE in order.

7. The method according to the claim 6, wherein the step of sequentially allocating one or multiple resource blocks comprising:

allocating the resource blocks corresponding to the multiple RRUs prior to allocating the resource blocks corresponding to the one RRU.

8. The method according to claim 7, wherein:

the service type comprising a broadcast service type, a multicast service type and a unicast service type,

wherein when the service type of the service flow is the broadcast service type, allocating the resource blocks corresponding to all of the RRUs of the base station.

9. The method according to claim 8, wherein when the service type of the service flow is a unicast service type, the step of associating the UE with one or more RRUs comprising:

determining the RRUs whose radio coverage covers the location of the UE;

associating the UE with the RRUs whose radio coverage covers the location of the UE; and

setting the MIMO scheme as the antenna scheme or the combination of the antenna scheme and the site diversity scheme.

10. The method according to claim 9, wherein when the part or all of the RRUs are associated with the UE, in receiving phase, the method further comprising:

receiving uplink sub streams respectively by the part or all of the RRUs associated with the UE through the resource blocks of the part or all of the RRUs; and

demodulating out of the received uplink sub streams.

11. The method according to claim 9, wherein when the part or all of the RRUs are associated with the UE, in transmission phase, the method further comprising:

transmitting downlink sub streams respectively to the UE from the part or all of the RRUs through the resource blocks of the part or all of the RRUs associated with the UE.

12. The method according to claim 8, wherein:

in the step of estimating the location of the UE, the method further comprising;

measuring at least one signal indicator between the UE and at least one of the RRUs of the base station, wherein the location of the UE is located in the radio coverage of the at least one of the RRUs;

when an average value or a weighted value of the at least one signal indicator is bigger than or equal to a threshold, setting the MIMO scheme as the antenna multiplexing scheme, or the combination of antenna multiplexing scheme and the site diversity scheme; and

when the average value or the weighted value of the at least one signal indicator is smaller than a threshold, setting the MIMO scheme as the antenna diversity scheme, or the combination of antenna diversity scheme and the site diversity scheme.

13. The method according to claim 12, wherein:

the signal indicator comprises one or multiple parameters to a signal strength, a signal quality, a propagation loss, propagation delay, and a distance between the UE and the at least one of the RRUs; and

the step of generating the UE information further comprising;

generating the UE information according to the at least one signal indicators between the UE and at least one of the RRUs of the base station.

14. The method according to claim 13, wherein the method further comprising:

monitoring the at least one signal indicator,

wherein when an average value or a weighted value of the at least one signal indicator reaches or crosses a preset threshold, determining whether to execute a handover process.

15. A base station of cooperative multiple-input-multiple-output (MIMO) wireless communication, the base station comprising:

a plurality of radio remote units (RRUs), wherein each of the RRUs respectively has a radio coverage and a plurality of antennas are coupled to each of the RRUs, wherein the RRUs locate on different geographical locations;

a plurality of baseband units (BBUs), respectively coupled between the data processing unit and the RRUs; and

a processor, coupled to the BBUs, and programmed to execute;

a data processing unit, coupled to the BBUs, receiving a service flow from an application layer service provider; and

a mapping unit, coupled to the BBUs and the data processing unit, deriving a service type of the service flow, wherein the service type comprises a broadcast service type, a multicast service type, and a unicast service type, receives a user equipment (UE) information comprising a location of the UE through the BBUs and the RRUs, and determining a MIMO scheme for modulating the service flow into a MIMO stream for the UE according to the service type and the UE information, wherein if the location of the UE is in an area within the radio coverage of at least two of the RRUs, the MIMO scheme of the UE is determined to be a site MIMO scheme performed by the at least two of the RRUs, wherein the MIMO scheme comprises an antenna scheme, or a combination of the antenna scheme and a site diversity scheme, wherein the antenna scheme comprises an antenna multiplexing scheme and an antenna diversity scheme,

wherein, the mapping unit allocates a plurality of resource blocks to part or all of the RRUs according to the MIMO scheme, the UE information and the service type, and transmits an allocation information to the data processing unit, wherein the resource blocks corresponds to part or all of the RRUs, and the allocation information corresponds to the allocated resource blocks, wherein the at least two of the RRUs cooperatively transmit the downlink sub streams for the UE according to the site MIMO scheme.

16. The base station according to claim 15, wherein the RRUs:

in transmission phase,

transmits a plurality of downlink sub streams according to the allocated resources blocks when receiving the downlink sub streams; and

in receiving phase,

receives a plurality of uplink sub streams according to the allocated resource blocks and transmits the uplink sub streams to the data processing unit via BBUs.

17. The base station according to claim 16, wherein the data processing unit

in transmission phase,

modulates the service flow into a MIMO stream by the MIMO scheme;

and

distributes the MIMO stream into the downlink sub streams according to the allocation information and transmits the downlink sub streams to the RRUs corresponding to the resource blocks via the BBUs.

18. The base station according to claim 17, wherein

the mapping unit detects the UE corresponding to the service flow through the BBUs and the RRUs;

and

the RRUs generates the UE information by estimating location of the UE, and the mapping unit associates the UE with one or more RRUs according to the UE information and the location of UE.

19. The base station according to claim 18, wherein the data processing unit

in receiving phase,

demodulates the service flow out of the uplink sub streams received through part or all of the RRUs that corresponding to the allocated resource blocks according to the MIMO scheme.

20. The base station according to claim 19, wherein:

the MIMO scheme comprising an antenna scheme, or a combination of the antenna scheme and a site diversity scheme, wherein the antenna scheme comprising an antenna multiplexing scheme and an antenna diversity scheme.

21. The base station according to claim 20, wherein the UE information comprises one or multiple parameters of signal strength, signal to interference ratio, round trip time, UE location and UE identifier.

22. The base station according to claim 21, wherein:

the mapping unit allocates one or multiple resource blocks sequentially according to the MIMO scheme, the service type, the location of the UE and the RRUs associated with the UE in order.

23. The base station according to the claim 22, wherein:

the mapping unit allocates the resource blocks corresponding to the multiple RRUs prior to allocates the resource blocks corresponding to the one RRU.

24. The base station according to claim 21, wherein:

the service type comprising a broadcast service type, a multicast service type and a unicast service type, wherein when the service type of the service flow is the broadcast service type, the mapping unit allocates the resource blocks corresponding to all of the RRUs of the base station.

25. The base station according to claim 24 wherein:

in transmission phase, when mapping unit determines that the service type of the service flow is the unicast service type, the mapping unit determines the RRUs whose radio coverage covers the location of the UE, and associates the RRUs whose radio coverage covers the location of the UE with the UE, and sets the MIMO scheme as the antenna scheme or the combination of the antenna scheme and the site diversity scheme.

26. The base station according to claim 24, wherein:

when estimating the location of the UE, the mapping unit measures at least one signal indicator between the UE and at least one of the RRUs of the base station, wherein the current location of the UE is located in the radio coverage of the at least one of the RRUs;

when an average value or a weighted value of the at least one signal indicator is bigger or equal to a threshold, the mapping unit sets the MIMO scheme as the antenna multiplexing scheme, or the combination of antenna multiplexing scheme and the site diversity scheme; and

when the average value or the weighted value of the at least one signal indicator is smaller than a threshold, the mapping unit sets the MIMO scheme as the antenna diversity scheme, or the combination of antenna diversity scheme and the site diversity scheme.

27. The base station according to claim 26, wherein:

the signal indicator comprises one or multiple parameters to a signal strength, a propagation loss, propagation delay, a signal quality and a distance between the UE and the at least one of the RRUs; and

the mapping unit generates the UE information according to the at least one signal indicators between the UE and at least one of the RRUs.

28. The base station according to claim 26, wherein:

the mapping unit monitors the at least one signal indicator,

wherein when an average value or weighted value of the at least one signal indicator is reaches or crosses a preset threshold, the mapping unit determines whether to execute a handover process.