TRANSMITTING APPARATUS, RECEIVING APPARATUS AND MULTIPLEX NUMBER CONTROLLING METHOD

• US 20090268621A1
• Filed: 06/01/2006
• Published: 10/29/2009
• Est. Priority Date: 06/03/2005
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Hiramatsu, Katsuhiko, Imai, Tomohiro, Kimura, Ryohei, Miyoshi, Kenichi, Yuda, Yasuaki, Hoshino, Masayuki
• Granted Patent: US 8,345,562 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0021 in which the algorithm uses adaptive thresholds
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER

Abstract

A spatial multiplex number controlling method and others wherein streams can be separated for each of receivers and the transmission efficiency can be improved. In a receiving apparatus, a PER is calculated from a history of CRC test results per stream multiplex number. A reception quality and an offset corresponding to the calculated PER are fed hack to a transmitting apparatus. The transmitting apparatus assigns, based on the fed-back reception quality and offset, the streams, thereby controlling the stream multiplex number.

Claims

1. A receiving apparatus comprising:

a receiving section that receives a stream multiplex signal subjected to stream multiplexing;

a spatial demultiplexing estimating section that estimates capacity of the receiving apparatus for demultiplexing the stream multiplex signal into individual streams, for each number of multiplexed streams;

an offset setting section that sets an offset for controlling the number of multiplexed streams based on the capacity;

a received quality measuring section that measures received quality of each stream based on the stream multiplex signal; and

a feedback section that feeds back information showing the offset and the received quality to a transmitting apparatus.

2. The receiving apparatus according to claim 1, wherein the spatial demultiplexing capacity estimating section comprises a memory section that stores a record of error detection results with the stream multiplex signal for each number of multiplexed streams, and estimates spatial demultiplexing capacity based on an error rate calculated from the record of error detection results.

3. The receiving apparatus according to claim 1, wherein the spatial demultiplexing capacity estimating section comprises a memory section that stores a record of error detection results with the stream multiplex signal for each coding rate of each stream and estimates spatial demultiplexing capacity based on an error rate calculated from the record of error detection results.

4. The receiving apparatus according to claim 1, wherein the spatial demultiplexing capacity estimating section calculates a tentative decision value of a symbol obtained by demodulating the stream multiplex signal and estimates spatial demultiplexing capacity based on whether a square distance between the calculated tentative decision value and a candidate point exceeds a predetermined threshold value.

5. The receiving apparatus according to claim 1 further comprising

a predicting section that predicts a number of multiplexing of the stream multiplex signal received by the receiving section, based on the received quality;

and

a memory section that stores a record of error detection results with the stream multiplex signal per difference between the predicted number of multiplexing and a number of multiplexing of the stream multiplex signal actually received by the receiving section.

6. A transmitting apparatus comprising:

a stream assigning section that controls a number of multiplexed streams by obtaining information showing an offset and received quality fed back from the receiving apparatus according to claim 1 and carrying out assignment of streams based on the obtained offset and received quality;

a modulation and coding scheme determining section that determines a modulation scheme and coding rate applied to the assigned streams based on the received quality of the assigned streams; and

a transmission processing section that performs transmission processing of transmission data using the assigned streams and the determined modulation scheme and coding rate.

7. The transmitting apparatus according to claim 6, further comprising a symbol inserting section that inserts a known symbol for estimating spatial demultiplexing capacity in the receiving apparatus into a transmission symbol.

8. The transmitting apparatus according to claim 6, further comprising a stream assignment adjusting section that voluntarily determines the number of multiplexed streams and designates the determined number of multiplexed streams to the stream assigning section.

9. A spatial multiplexing control method comprising:

at the receiving apparatus;

estimating performance of the receiving apparatus for demultiplexing in the receiving apparatus a stream multiplex signal subjected to stream multiplexing into individual streams, for each number of multiplexed streams;

setting an offset for controlling the number of multiplexed streams based on the capacity;

measuring received quality of each stream based on the stream multiplex signal; and

feeding back information showing the offset and the received quality to a transmitting apparatus, and

at the transmitting apparatus;

controlling the number of multiplexed streams by carrying out assignment of streams based on the information showing the offset and received quality fed back from the receiving apparatus.

10. A communication system comprising:

a receiving apparatus that comprises;

a receiving section that receives a stream multiplex signal subjected to stream multiplexing;

a spatial demultiplexing capacity estimating section that estimates capacity of the receiving apparatus for demultiplexing the stream multiplex signal into individual streams, for each number of multiplexed streams;

an offset setting section that sets an offset for controlling the number of multiplexed streams based on the capacity;

a received quality measuring section that measures received quality of each stream based on the stream multiplex signal; and

a feedback section that feeds back information showing the offset and the received quality to a transmitting apparatus; and

the transmitting apparatus that comprises;

a stream assigning section that controls the number of multiplexed streams by obtaining the information showing the offset and received quality fed back from the receiving apparatus and carrying out assignment of streams based on the obtained offset and received quality;

a modulation and coding scheme determining section that determines a modulation scheme and coding rate applied to the assigned streams, based on the received quality of the assigned streams; and

a transmission processing section that performs transmission processing of transmission data using the assigned streams and the determined modulation scheme and coding rate.