Wireless local area network system using STBC having backward compatibility with prior standards

• US 20050281354A1
• Filed: 11/24/2004
• Published: 12/22/2005
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Kim, Joonsuk
• Granted Patent: US 7,660,362 B2
• Time in Patent Office: Days
• US Class Current: 375/299
• CPC Class Codes: H04B 7/02 Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas RAKE receivers H04B1/7115
• CPC Class Codes: H04L 1/0668 Orthogonal systems, e.g. using Alamouti codes

Abstract

A method of communicating data to a receiving antenna from N transmitting antennas, where N is an integer, includes the steps of determining whether a legacy transmission mode has been selected, producing N data streams from outbound data, and applying the N data streams to a space/time encoder to produce N encoded signals. When the legacy transmission mode has not been selected, the N encoded signals are transmitting from N transmitting antennas and when the legacy transmission mode has been selected, the one encoded signal is transmitted from one of the N transmitting antennas. The legacy transmission mode allows receivers to receive and process transmitted signals when the receivers are only configured to receive the transmitted signals from a single transmitting antenna.

Claims

1. A method of communicating data to a receiving antenna from N transmitting antennas, where N is an integer, the method comprising the steps of:

determining whether a legacy transmission mode has been selected;

producing N data streams from outbound data;

applying the N data streams to a space/time encoder to produce N encoded signals;

when the legacy transmission mode has not been selected;

transmitting the N encoded signals from N transmitting antennas; and

when the legacy transmission mode has been selected;

transmitting the one encoded signal from one of the N transmitting antennas;

wherein the legacy transmission mode allows receivers to receive and process transmitted signals when the receivers are only configured to receive the transmitted signals from a single transmitting antenna.

2. The method of claim 1, wherein when the legacy transmission mode has not been selected, the step of applying the N data streams to the space/time encoder comprises producing at least one conjugate encoded signal.

3. The method of claim 1, wherein when the legacy transmission mode has not been selected, the step of applying the N data streams to the space/time encoder comprises adding a Long Training Sequence immediately before data in a frame.

4. The method of claim 3, wherein the step of adding a Long Training Sequence is performed such that a receiver processor will process the frame in a Space/Time Block Coding mode.

5. The method of claim 1, wherein when the legacy transmission mode has not been selected, the step of applying the N data streams to the space/time encoder comprises encoding the two data streams so that channel estimates can be performed by the receivers according to:

$\left[\begin{array}{c}{\tilde{h}}_1\\ {\tilde{h}}_2\end{array}\right]=C^{*}\times <br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}\underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>c<br><br>\left(t_i\right)<br><br>}^2& 0\\ 0& \underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>c<br><br>\left(t_i\right)<br><br>}^2\end{array}\right]\times <br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{\tilde{n}}_1\\ {\tilde{n}}_2\end{array}\right],\mathrm{where}<br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}c<br><br>\left(t_0\right)& -c^{*}<br><br>\left(t_1\right)\\ c<br><br>\left(t_1\right)& c^{*}<br><br>\left(t_0\right)\end{array}\right]<br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{n}_1\\ n_2\end{array}\right]=C\times <br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{n}_1\\ n_2\end{array}\right]$

where where r_i(t) and c_i(t) are the received and transmitted signals, respectively, n_i represent noise terms and h_i represents relationships between signals sent from the two transmitting antennas to the receiving antenna.

6. A method according to claim 5, wherein the step of applying the N data streams to the space/time encoder comprises encoding the two data streams so that data can be retrieved by the receivers according to:

$\left[\begin{array}{c}\tilde{c}<br><br>\left(t_0\right)\\ {\tilde{c}}^{*}<br><br>\left(t_1\right)\end{array}\right]=H^{*}\times <br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r^{*}<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}\underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>h_i<br><br>}^2& 0\\ 0& \underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>h_i<br><br>}^2\end{array}\right]\times <br><br>\left[\begin{array}{c}c<br><br>\left(t_0\right)\\ c^{*}<br><br>\left(t_1\right)\end{array}\right]+\left[\begin{array}{c}{\tilde{n}}_1\\ {\tilde{n}}_2\end{array}\right].$

7. A method according to claim 1, wherein when the legacy transmission mode has been selected, the receivers which are capable of processing a data frame in a Space/Time Block Coding mode bypass the Space/Time Block Coding mode.

8. A method according to claim 1, wherein the receivers that are only configured to receive the transmitted signals from a single transmitting antenna comprise receivers that comply with standards of IEEE 802.11.

9. A transmitter for communicating data to a receiving antenna from N transmitting antennas, where N is an integer, comprising:

determining means for determining whether a legacy transmission mode has been selected;

producing means for producing N data streams from outbound data;

encoding means for space/time encoding the N data streams to produce N encoded signals; and

N transmitting antenna means for transmitting the N encoded signals or one signal;

wherein the N encoded signals are transmitted from N transmitting antenna means when the legacy transmission mode has not been selected, the one encoded signal is transmitted from one of the N transmitting antenna means when the legacy transmission mode has been selected, and the legacy transmission mode allows receivers to receive and process transmitted signals when the receivers are only configured to receive the transmitted signals from a single transmitting antenna.

10. The transmitter of claim 9, wherein the encoding means is configured to produce at least one conjugate encoded signal, when the legacy transmission mode has not been selected.

11. The transmitter of claim 9, wherein the encoding means is configured to add a Long Training Sequence immediately before data in a frame, wherein when the legacy transmission mode has not been selected.

12. The transmitter of claim 11, wherein the encoding means is configured to add a Long Training Sequence such that a receiver processor will process the frame in a Space/Time Block Coding mode.

13. The transmitter of claim 9, wherein when the legacy transmission mode has not been selected, the encoding means is configured to encode the two data streams so that channel estimates can be performed by the receivers according to:

$\left[\begin{array}{c}{\tilde{h}}_1\\ {\tilde{h}}_2\end{array}\right]=C^{*}\times <br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}\underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>c<br><br>\left(t_i\right)<br><br>}^2& 0\\ 0& \underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>c<br><br>\left(t_i\right)<br><br>}^2\end{array}\right]\times <br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{\tilde{n}}_1\\ {\tilde{n}}_2\end{array}\right],\mathrm{where}<br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}c<br><br>\left(t_0\right)& -c^{*}<br><br>\left(t_1\right)\\ c<br><br>\left(t_1\right)& c^{*}<br><br>\left(t_0\right)\end{array}\right]<br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{n}_1\\ n_2\end{array}\right]=C\times <br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{n}_1\\ n_2\end{array}\right]$

where where r_i(t) and c_i(t) are the received and transmitted signals, respectively, n_i represent noise terms and h_i represents relationships between signals sent from the two transmitting antennas to the receiving antenna.

14. A transmitter according to claim 13, wherein the encoding means is configured to encode the two data streams so that data can be retrieved by the receivers according to:

$\left[\begin{array}{c}\tilde{c}<br><br>\left(t_0\right)\\ {\tilde{c}}^{*}<br><br>\left(t_1\right)\end{array}\right]=H^{*}\times <br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r^{*}<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}\underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>h_i<br><br>}^2& 0\\ 0& \underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>h_i<br><br>}^2\end{array}\right]\times <br><br>\left[\begin{array}{c}c<br><br>\left(t_0\right)\\ c^{*}<br><br>\left(t_1\right)\end{array}\right]+\left[\begin{array}{c}{\tilde{n}}_1\\ {\tilde{n}}_2\end{array}\right].$

15. A transmitter according to claim 9, wherein the encoding means is configured to encode the data streams such that the receivers which are capable of processing a data frame in a Space/Time Block Coding mode bypass the Space/Time Block Coding mode, when the legacy transmission mode has been selected

16. A transmitter according to claim 9, wherein the receivers that are only configured to receive the transmitted signals from a single transmitting antenna comprise receivers that comply with standards of IEEE 802.11.

17. A transmitter for communicating data to a receiving antenna from N transmitting antennas, where N is an integer, comprising:

a legacy switch indicator, configured to determine whether a legacy transmission mode has been selected;

a demultiplexer, configured to produce N data streams from outbound data;

a space/time encoder, configured to encode the N data streams to produce N encoded signals; and

N transmit antennas, configured to transmit the N encoded signals or one signal;

wherein the N encoded signals are transmitted from N transmit antennas when the legacy transmission mode has not been selected, one encoded signal is transmitted from one of the N transmit antennas when the legacy transmission mode has been selected, and the legacy transmission mode allows receivers to receive and process transmitted signals when the receivers are only configured to receive the transmitted signals from a single transmitting antenna.

18. The transmitter of claim 17, wherein the space/time encoder is configured to produce at least one conjugate encoded signal, when the legacy transmission mode has not been selected.

19. The transmitter of claim 17, wherein the space/time encoder is configured to add a Long Training Sequence immediately before data in a frame, wherein when the legacy transmission mode has not been selected.

20. The transmitter of claim 19, wherein the space/time encoder is configured to add a Long Training Sequence such that a receiver processor will process the frame in a Space/Time Block Coding mode.

21. The transmitter of claim 17, wherein when the legacy transmission mode has not been selected, wherein the space/time encoder is configured to encode the two data streams so that channel estimates can be performed by the receivers according to:

$\left[\begin{array}{c}{\tilde{h}}_1\\ {\tilde{h}}_2\end{array}\right]=C^{*}\times <br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}\underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>c<br><br>\left(t_i\right)<br><br>}^2& 0\\ 0& \underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>c<br><br>\left(t_i\right)<br><br>}^2\end{array}\right]\times <br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{\tilde{n}}_1\\ {\tilde{n}}_2\end{array}\right],\mathrm{where}<br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}c<br><br>\left(t_0\right)& -c^{*}<br><br>\left(t_1\right)\\ c<br><br>\left(t_1\right)& c^{*}<br><br>\left(t_0\right)\end{array}\right]<br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{n}_1\\ n_2\end{array}\right]=C\times <br><br>\left[\begin{array}{c}{h}_1\\ h_2\end{array}\right]+\left[\begin{array}{c}{n}_1\\ n_2\end{array}\right]$

where where r_i(t) and c_i(t) are the received and transmitted signals, respectively, n_i represent noise terms and h_i represents relationships between signals sent from the two transmitting antennas to the receiving antenna.

22. A transmitter according to claim 21, wherein the space/time encoder is configured to encode the two data streams so that data can be retrieved by the receivers according to:

$\left[\begin{array}{c}\tilde{c}<br><br>\left(t_0\right)\\ {\tilde{c}}^{*}<br><br>\left(t_1\right)\end{array}\right]=H^{*}\times <br><br>\left[\begin{array}{c}r<br><br>\left(t_0\right)\\ r^{*}<br><br>\left(t_1\right)\end{array}\right]=\left[\begin{array}{cc}\underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>h_i<br><br>}^2& 0\\ 0& \underset{i=1}{\overset{2}{\sum <br><br>}}<br><br>{<br><br>h_i<br><br>}^2\end{array}\right]\times <br><br>\left[\begin{array}{c}c<br><br>\left(t_0\right)\\ c^{*}<br><br>\left(t_1\right)\end{array}\right]+\left[\begin{array}{c}{\tilde{n}}_1\\ {\tilde{n}}_2\end{array}\right].$

23. A transmitter according to claim 17, wherein the space/time encoder is configured to encode the data streams such that the receivers which are capable of processing a data frame in a Space/Time Block Coding mode bypass the Space/Time Block Coding mode, when the legacy transmission mode has been selected

24. A transmitter according to claim 17, wherein the receivers that are only configured to receive the transmitted signals from a single transmitting antenna comprise receivers that comply with standards of IEEE 802.11.