Wireless lan compatible multi-input multi-output system

• US 20040258025A1
• Filed: 03/05/2004
• Published: 12/23/2004
• Est. Priority Date: 06/18/2003
• Status: Active Grant

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: University of Florida (State University System of Florida)
• Inventors: Liu, Jianhua, Li, Jian
• Granted Patent: US 7,110,350 B2
• Time in Patent Office: Days
• US Class Current: 370/334
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0656 Cyclotomic systems, e.g. Bell Labs Layered Space-Time [BLAST]
• CPC Class Codes: H04L 27/2602 Signal structure

Abstract

A system and method for enhancing the data rate of a WLAN. Through the deployment of a MIMO system, the data rate ordinarily expected of a SISO type system can be doubled. Yet, the MIMO system of the present invention can remain backward compatible with conventional WLAN standards implemented by typical SISO type system. In particular, the packet preamble of the MIMO packet of the present invention is similar to that of a conventional SISO system so as to be backward compatible with conventional SISO receivers. Additionally, the data model of the MIMO system can be configured to support the detection of symbols in the MIMO packet of the present invention. Importantly, the present invention can include a least squares soft-detector for use in a wireless LAN compatible MIMO system.

Claims

1. A method of wirelessly conveying data comprising the steps of:

identifying an electronic document to be wirelessly transmitted from a transmission location to a receiving location;

digitally encoding said electronic document into a plurality of data packets using a soft encoder, each data packet having a MIMO preamble;

simultaneously transmitting said packets using a plurality of transmission antennas; and

based upon said transmitted packets, generating said electronic document at said receiving location.

2. The method of claim 1, said digital encoding step using a channel coding technique to implement forward error correction.

3. The method of claim 2, wherein said channel coding technique is a convolutional encoding technique.

4. The method of claim 1, wherein said transmitting step further comprises the step of:

introducing temporal and spatial correlation into signals transmitted from different ones of said plurality of transmission antennas using a space-time coding technique.

5. The method of claim 1, wherein said transmitting step further comprises the step of:

scattering data bits of selective ones of said packets across a plurality of said antennas using a spatial interleaving technique.

6. The method of claim 1, said generating step further comprising the steps of:

receiving said packets using a plurality of receiving antennas;

digitally decoding said packets using a soft decoder; and

responsively generating said electronic document at said receiving location.

7. The method of claim 6, wherein said decoding step utilizes an unstructured least squares estimation technique.

8. The method of claim 6, wherein said decoding step further comprises the step of:

computing a signal to noise ratio of received signals that is used during said decoding process.

9. A machine-readable storage having stored thereon, a computer program having a plurality of code sections, said code sections executable by a machine for causing the machine to perform the steps of:

identifying an electronic document to be wirelessly transmitted from a transmission location to a receiving location;

digitally encoding said electronic document into a plurality of data packets using a soft encoder, each data packet having a MIMO preamble;

simultaneously transmitting said packets using a plurality of transmission antennas; and

based upon said transmitted packets, generating said electronic document at said receiving location.

10. The machine-readable storage of claim 9, said digital encoding step using a channel coding technique to implement forward error correction.

11. The machine-readable storage of claim 10, wherein said channel coding technique is a convolutional encoding technique.

12. The machine-readable storage of claim 9, wherein said transmitting step further comprises the step of:

introducing temporal and spatial correlation into signals transmitted from different ones of said plurality of transmission antennas using a space-time coding technique.

13. The machine-readable storage of claim 9, wherein said transmitting step further comprises the step of:

scattering data bits of selective ones of said packets across a plurality of said antennas using a spatial interleaving technique.

14. The machine-readable storage of claim 9, said generating step further comprising the steps of:

receiving said packets using a plurality of receiving antennas;

digitally decoding said packets using a soft decoder; and

responsively generating said electronic document at said receiving location.

15. The machine-readable storage of claim 14, wherein said decoding step utilizes an unstructured least squares estimation technique.

16. The machine-readable storage of claim 14, wherein said decoding step further comprises the step of:

computing a signal to noise ratio of received signals that is used during said decoding process.

17. A machine readable storage having stored thereon a computer program for soft-detecting soft-information required by a convolutional decoder in a wireless multi-input multi-output (MIMO) system, said computer program comprising a routine set of instructions executable within a computing machine which when executed can cause the machine to perform the steps of:

producing an unstructured least squares estimate for a time-varying channel in the MIMO system;

computing a SNR for said produced unstructured least squares estimate; and

providing both said unstructured least squares estimate and said variance to the convolutional decoder as the soft-information.

18. A system for wireless conveying digital information comprising:

transmitting source having a plurality of transmitting antennas, wherein data is transmitted from said plurality of transmitting antennas simultaneously;

a channel encoder communicatively linked to said transmitting source, said channel encoder configured to encode electronic documents into a plurality of packets, each packet having a MIMO preamble;

a receiving mechanism having a plurality of receiving antennas; and

a soft decoder communicatively linked to said receiving mechanism, said channel encoder configured to encode electronic documents based on packets of data received from said plurality of antennas.

19. The system of claim 18, wherein said transmitting source introduces temporal and spatial correlation into signals transmitted from different ones of said plurality of transmission antennas using a space-time coding technique.

20. The system of claim 18, wherein said channel encoder utilizes a channel coding technique to implement forward error correction.

21. The system of claim 20, wherein said channel coding technique is a convolutional encoding technique.

22. The system of claim 18, wherein said soft decoder calculates a plurality of unstructured least squares estimates when decoding received signals.

23. The system of claim 18, wherein said soft decoder calculate a signal to noise ratio of received signals when decoding said received signals.

24. The system of claim 18, further comprising:

an interleaver communicatively linked to said transmitting source; and

a deinterleaver communicatively linked to said receiving mechanism.