Orthogonalized spatial multiplexing for wireless communication

• US 6,934,320 B2
• Filed: 04/19/2002
• Issued: 08/23/2005
• Est. Priority Date: 04/19/2002
• Status: Expired due to Fees

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Sottani, Emiliano, Tujkovic, Djordje
• Primary Examiner(s): Tran, Khai
• Assistant Examiner(s): Lugo, David B.
• Application Number:
  US10/127,327
• Publication Number:
  US 20030198282A1
• Time in Patent Office: 1,222 Days
• Field of Search: 375/140, 375/141, 375/146, 375/260, 375/267, 375/299
• US Class Current: 375/146
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 1/006 Trellis-coded modulation
• 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]

Abstract

A method and system for processing information data in a wireless communications system for reducing the complexity in spatial multiplexing of signals over different transmit antennas. In orthogonalized spatial multiplexing with the resolution of one, encoded data are interleaved and converted into a plurality of parallel sub-streams. Each sub-stream is then spreaded with a user specific spreading code with an intentional delay offset of few chips prior to modulating the encoded data for transmission. Likewise, in orthogonalized spatial multiplexing with the resolution of two, encoded data are interleaved and converted into a plurality of parallel sub-stream pairs. Each sub-stream pair is spreaded pairwise with a user specific spreading code with an intentional delay offset of few chips.

Claims

1. A method of processing information data in a wireless communications system having a plurality of transmit antennas for transmission, wherein the method comprises:

encoding the information data for providing encoded data;

spreading the encoded data with a spreading code for providing a first spread data stream;

spreading the encoded data with at least one delayed version of the spreading code for providing at least one second spread data stream;

modulating the first and second spread data streams for providing modulated signals; and

conveying the modulated signals to the transmit antennas for transmission, said method characterized by

separating the encoded data into data sub-streams prior to said spreading, the data sub-streams including at least a first group of encoded data and a second group of encoded data such that the first spread data stream is indicative of the first group of encoded data and said at least one second spread data stream is indicative of the second group of encoded data, wherein the encoded data comprises a pair of mutually orthogonal substream symbols, said method further characterized in that

the data sub-streams comprise at least a first pairwise substream and a second pairwise substream of the substream symbol pair, such that the first group of encoded data comprises the first pairwise substreams and the second group of encoded data comprises the second pairwise substreams.

2. A method of processing information data in a wireless communications system having a plurality of transmit antennas for transmission, wherein the method comprises:

encoding the information data for providing encoded data;

spreading the encoded data with a spreading code for providing a first spread data stream;

spreading the encoded data with at least one delayed version of the spreading code for providing at least one second spread data stream;

modulating the first and second spread data streams for providing modulated signals; and

conveying the modulated signals to the transmit antennas for transmission, said method characterized by

separating the encoded data into data sub-streams prior to said spreading, the data sub-streams including at least a first group of encoded data and a second group of encoded data such that the first spread data stream is indicative of the first group of encoded data and said at least one second spread data stream is indicative of the second group of encoded data, wherein the encoded data comprises a group of N mutually orthogonal substream symbols, with N being a positive integer greater than 2, said method further characterized in that

the data substreams comprise at least a first group of N substreams and a second group of N substreams of the substream symbols, such that the first group of encoded data comprises the first group of N substreams and the second group of encoded data comprises the second group of N substreams.

3. A transmitter for processing information data for providing modulated signals for transmission via a plurality of transmit antennas, wherein the transmitter comprises:

means, responsive to the information data, for providing encoded data;

means for spreading the encoded data with a spreading code for providing a first spread data stream, and for spreading the encoded data with at least one delayed version of the spreading code for providing at least one second spread data stream; and

means for modulating the first and second spread data streams for providing the modulated signals, characterized by

means, responsive to the encoded data, for separating the encoded data into data sub-streams prior to the spreading of the encoded data by the spreading mean the data sub-streams including at least a first group of encoded data and a second group of encoded data such that the first spread data stream is indicative of the first group of encoded data and said at least one second spread data stream is indicative of the second group of encoded data, wherein the encoded data comprises a pair of mutually orthogonal substream symbols, said transmitter further characterized in that

the data substreams comprise at least a first pairwise substream and a second pairwise substream of the substream symbol pair, such that the first group of encoded data comprises the first pairwise substreams and the second group of encoded data comprises the second pairwise substreams.

4. A transmitter for processing information data for providing modulated signals for transmission via a plurality of transmit antennas, wherein the transmitter comprises:

means, responsive to the information data, for providing encoded data;

means for spreading the encoded data with a spreading code for providing a first spread data stream, and for spreading the encoded data with at least one delayed version of the spreading code for providing at least one second spread data stream; and

means for modulating the first and second spread data streams for providing the modulated signals, characterized by

means, responsive to the encoded data, for separating the encoded data into data sub-streams prior to the spreading of the encoded data by the spreading means, the data sub-streams including at least a first group of encoded data and a second group of encoded data such that the first spread data stream is indicative of the first group of encoded data and said at least one second spread data stream is indicative of the second group of encoded data, wherein the encoded data comprises a group of N mutually orthogonal substream symbols, with N being a positive integer greater than 2, said transmitter further characterized in that

the data substreams comprise at least a first group of N substreams and a second group of N substreams of the substream symbols, such that the first group of encoded data comprises the first group of N substreams and the second group of encoded data comprises the second group of N substreams.

5. A wireless communications system comprising a transmitter and a receiver, the transmitter having a plurality of transmit antennas for transmitting modulated signals indicative of information data and the receiver having a plurality of receive antennas for receiving modulated signals, wherein the transmitter comprises:

means, responsive to the information data, for providing encoded data;

means for spreading the encoded data with a spreading code for providing a first spread data stream, and for spreading the encoded data with at least one delayed version of the spreading code for providing at least one second spread data stream; and

means for modulating the first and second spread data streams for providing the modulated signals, characterized by;

means, responsive to the encoded data, for separating the encoded data into data sub-streams, prior to the spreading of the encoded data by the spreading means, the data sub-streams including at least a first group of encoded data and a second group of encoded data such that the first spread data stream is indicative of the first group of encoded data and said at least one second spread data stream is indicative of the second group of encoded data, wherein the encoded data comprises a pair of mutually orthogonal substream symbols, said system further characterized in that

the data sub-streams comprise at least a first pairwise substream and a second pairwise substream of the substream symbol pair, such that the first group of encoded data comprises the first pairwise substreams and the second group of encoded data comprises the second pairwise substreams.