US 8,265,675 B2Granted

MIMO wireless communication system and method by a plurality of base stations and mobile station

AssigneeNEC Corporation

InventorsMariko Matsumoto, Shousei Yoshida

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Abstract

A MIMO wireless communication system capable of relaxing a reduction in a transmission rate on a cell end far from a base station and ensuring a high transmission rate for a mobile station, irrespectively of a distance from the base station is provided. In a state 1, the mobile station 21 checks a propagation line quality and instructs only the first base station 11 to transmit data to the mobile station 21. In a state 2, the mobile station 21 issues a request to divide the data to the first base station 11 and the second base station 12 and to transmit the divided data to the mobile station 21, and holds MIMO communication with the two base stations. In a state 3, the mobile station 21 requests only the second base station 12 to transmit the data and communicates with the second base station 12.

Claims28

Dependent claims

A wireless communication system including a plurality of base stations and at least one mobile station, wherein

the plurality of base stations include a unit distributing data addressed to a certain mobile station between two or more base stations selected from a group of base stations that can simultaneously communicate with the certain mobile station if a predetermined data rate cannot be obtained by data communication between the certain mobile station and a single base station, and simultaneously transmitting the distributed data from the respective base stations to the certain mobile station by a MIMO (Multi-Input Multi-Output) transmission method, the distributed data being different from the respective base stations;
the at least one mobile station includes a plurality of antennas and a unit receiving the data transmitted from the selected base stations by the MIMO transmission method, by a MIMO reception method using the plurality of antennas, and performs data communication only with a single base station by a non-MIMO transmission or reception method if the predetermined data rate can be obtained by the data communication between the certain mobile station and the single base station;
and
the selection of base stations is carried out by:
measuring transmission line quality between the mobile station and each of peripheral base stations;
notifying the base stations of the measured transmission line quality;
receiving communicable data rates from the base stations;
rearranging the received data rates in a descending order;
if a maximum data rate among the received data rates is higher than a predetermined data rate, deciding to select the base station communicable at the maximum data rate;
if the maximum data rate is not higher, calculating the number k of base stations satisfying that a sum of data rates of top k base stations in descending order is higher than the predetermined data rate;
if the calculated number k exceeds a number N of MIMO antennas owned by the mobile station, deciding to select top N base stations;
and if the calculated number k does not exceed the number N, deciding to select top k base stations.

9 more elements

A wireless communication system including a base station constituting a plurality of sectors and at least one mobile station, wherein

the base station includes a unit distributing data addressed to a certain mobile station between two or more sectors selected from a group of sectors that can simultaneously communicate with the certain mobile station if a predetermined data rate cannot be obtained by data communication between the certain mobile station and a single sector, and simultaneously transmitting the distributed data from the respective sectors to the certain mobile station by a MIMO transmission method, the distributed data being different from the respective sectors;
the at least one mobile station includes a plurality of antennas and a unit receiving the data transmitted from the selected sectors by the MIMO transmission method, by a MIMO reception method using the plurality of antennas, and performs data communication only with a single sector by a non-MIMO transmission or reception method if the predetermined data rate can be obtained by the data communication between the certain mobile station and the single sector;
and
the selection of sectors is carried out by:
measuring transmission line quality between the mobile station and each of peripheral sectors;
notifying the base station of the measured transmission line quality;
receiving communicable data rates from the base station;
rearranging the received data rates in a descending order;
if a maximum data rate among the received data rates is higher than a predetermined data rate, deciding to select the sector communicable at the maximum data rate;
if the maximum data rate is not higher, calculating the number k of sectors satisfying that a sum of data rates of top k sectors in descending order is higher than the predetermined data rate;
if the calculated number k exceeds a number N of MIMO antennas owned by the mobile station, deciding to select top N sectors;
and if the calculated number k does not exceed the number N, deciding to select top k sectors.

9 more elements

A wireless communication method by a plurality of base stations and at least one mobile station, including steps of:

causing the plurality of base stations to distribute data addressed to a certain mobile station between two or more base stations selected so as to satisfy a predetermined data rate from a group of base stations that can simultaneously communicate with the certain mobile station if the predetermined data rate cannot be obtained by data communication between the certain mobile station and a single base station, and to simultaneously transmit the distributed data from the respective base stations to the certain mobile station by a MIMO transmission method, the distributed data being different from the respective base stations;
causing the at least one mobile station having a plurality of antennas to receive the data transmitted from the selected base stations by the MIMO transmission method, by a MIMO reception method using the plurality of antennas, and to perform data communication only with a single base station by a non-MIMO transmission or reception method if the predetermined data rate can be obtained by the data communication between the certain mobile station and the single base station;
and
the selection of base stations is carried out by:
measuring transmission line quality between the mobile station and each of peripheral base stations;
notifying the base stations of the measured transmission line quality;
receiving communicable data rates from the base stations;
rearranging the received data rates in a descending order;
if a maximum data rate among the received data rates is higher than a predetermined data rate, deciding to select the base station communicable at the maximum data rate;
if the maximum data rate is not higher, calculating the number k of base stations satisfying that a sum of data rates of top k base stations in descending order is higher than the predetermined data rate;
if the calculated number k exceeds a number N of MIMO antennas owned by the mobile station, deciding to select top N base stations;
and if the calculated number k does not exceed the number N, deciding to select top k base stations.

9 more elements

A wireless communication method by a plurality of base stations constituting a plurality of sectors and at least one mobile station, including steps of:

causing the plurality of base stations to distribute data addressed to a certain mobile station between two or more sectors selected from a group of sectors that can simultaneously communicate with the certain mobile station if a predetermined data rate cannot be obtained by data communication between the certain mobile station and a single sector, and simultaneously transmit the distributed data from the respective sectors to the certain mobile station by a MIMO transmission method, the distributed data being different from the respective sectors;
causing the at least one mobile station having a plurality of antennas to receive the data transmitted from the selected sectors by the MIMO transmission method, by a MIMO reception method using the plurality of antennas, and to perform data communication only with a single sector by a non-MIMO transmission or reception method if the predetermined data rate can be obtained by the communication between the certain mobile station and the single sector;
and
the selection of sectors is carried out by:
measuring transmission line quality between the mobile station and each of peripheral sectors;
notifying the base station of the measured transmission line quality;
receiving communicable data rates from the base station;
rearranging the received data rates in a descending order;
if a maximum data rate among the received data rates is higher than a predetermined data rate, deciding to select the sector communicable at the maximum data rate;
if the maximum data rate is not higher, calculating the number k of sectors satisfying that a sum of data rates of top k sectors in descending order is higher than the predetermined data rate;
if the calculated number k exceeds a number N of MIMO antennas owned by the mobile station, deciding to select top N sectors;
and if the calculated number k does not exceed the number N, deciding to select top k sectors.

9 more elements

A wireless mobile station device comprising:

a plurality of antennas of MIMO reception for receiving signals from two or more base stations selected from a group of base stations that can simultaneously communicate with the wireless mobile station device if a predetermined data rate cannot be obtained by data communication between the wireless mobile station device and a single base station;
a MIMO separating unit separating the signals transmitted from the selected base stations according to transmission line characteristics of the respective base stations;
a demodulating unit demodulating the separated signals from the respective base stations;
a decoding and MIMO data combining unit decoding the demodulated signals and for combining the signals from the respective base stations;
and
a control unit exerting a control to receive the signals from the selected base stations by a MIMO transmission or reception method, and to receive a signal from a single base station by a non-MIMO transmission or reception method if the predetermined data rate can be obtained by data communication between the wireless mobile station device and the single base station,
wherein the selection of base stations is carried out by:
measuring transmission line quality between the mobile station and each of peripheral base stations;
notifying the base stations of the measured transmission line quality;
receiving communicable data rates from the base stations;
rearranging the received data rates in a descending order;
if a maximum data rate among the received data rates is higher than a predetermined data rate, deciding to select the base station communicable at the maximum data rate;
if the maximum data rate is not higher, calculating the number k of base stations satisfying that a sum of data rates of top k base stations in descending order is higher than the predetermined data rate;
if the calculated number k exceeds a number N of MIMO antennas owned by the mobile station, deciding to select top N base stations;
and if the calculated number k does not exceed the number N, deciding to select top k base stations.

12 more elements

A radio network controller comprising:

a network communication unit being connected to a network and holding a communication;
a distributing unit distributing data addressed to a certain mobile station between two or more base stations selected from a group of base stations that can simultaneously communicate with the certain mobile station if a predetermined data rate cannot be obtained by data communication between the certain mobile station and a single base station, and causing the two or more base stations to simultaneously transmit the distributed data from the respective base stations to the certain mobile station by a MIMO transmission method, the distributed data being different from the respective base stations, and to transmit the data addressed to the mobile station to a single base station by a non-MIMO transmission method if the predetermined data rate can be obtained by data communication between the certain mobile station and the single base station,
wherein the selection of base stations is carried out by:
measuring transmission line quality between the mobile station and each of peripheral base stations;
notifying the base stations of the measured transmission line quality;
receiving communicable data rates from the base stations;
rearranging the received data rates in a descending order;
if a maximum data rate among the received data rates is higher than a predetermined data rate, deciding to select the base station communicable at the maximum data rate;
if the maximum data rate is not higher, calculating the number k of base stations satisfying that a sum of data rates of top k base stations in descending order is higher than the predetermined data rate;
if the calculated number k exceeds a number N of MIMO antennas owned by the mobile station, deciding to select top N base stations;
and if the calculated number k does not exceed the number N, deciding to select top k base stations.

8 more elements

A wireless base station device comprising:

a plurality of antennas for MIMO transmission;
a transmission data selecting unit partially selecting, from among data addressed to a single mobile station, signals allocated to the wireless base station device in the case of MIMO transmission or reception with two or more base stations selected from a group of base stations that can simultaneously communicate with the single mobile station if a predetermined data rate cannot be obtained by data communication between the single mobile station and a single base station;
and
a control unit exerting a control to transmit the selected signals from the wireless base station device to the single mobile station in the case of MIMO transmission or reception with the selected base stations, and to cause the selecting unit either to select all the data for the single mobile station or not to select any of the data for the single mobile station in a state of a non-MIMO transmission or reception with the the base station if the predetermined data rate can be obtained by data communication between the single mobile station and the single base station,
wherein the selection of base stations is carried out by:
measuring transmission line quality between the mobile station and each of peripheral base stations;
notifying the base stations of the measured transmission line quality;
receiving communicable data rates from the base stations;
rearranging the received data rates in a descending order;
if a maximum data rate among the received data rates is higher than a predetermined data rate, deciding to select the base station communicable at the maximum data rate;
if the maximum data rate is not higher, calculating the number k of base stations satisfying that a sum of data rates of top k base stations in descending order is higher than the predetermined data rate;
if the calculated number k exceeds a number N of MIMO antennas owned by the mobile station, deciding to select top N base stations;
and if the calculated number k does not exceed the number N, deciding to select top k base stations.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/098,917Filed 7 Apr 2008 · continuation
Priority: JP 2005-2949627 Oct 2005
Published: US 2008/0192682 A114 Aug 2008
Granted: 11 Sep 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04B 7/0413
Using two or more spaced independent antennas: mIMO systems
H04W 36/304
By measured or perceived connection quality data: due to measured or perceived resources with higher communication quality
H04W 36/18
Performing reselection for specific purposes: for allowing seamless reselection, e.g. soft reselection
H04B
Transmission