Method of assigning a spreading sequence to a user of a telecommunications network

• US 7,342,910 B2
• Filed: 10/06/2005
• Issued: 03/11/2008
• Est. Priority Date: 09/13/1999
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Mottier, David, Castelain, Damien
• Primary Examiner(s): Shah; Chirag G.
• Application Number:
  US11/243,983
• Publication Number:
  US 20060029012A1
• Time in Patent Office: 887 Days
• Field of Search: None
• US Class Current: 370/342
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04L 5/026 using code division

Abstract

An apparatus and method for a Multi-Carrier Code Division Multiple Access (“MC-CDMA”) transmission network is disclosed. In the MC-CDMA transmission network a plurality of spreading sequences are assigned to individual users from a plurality of predetermined spreading sequences. The spreading sequences are assigned to users in order to minimize the interference created by the assignment of spreading sequences.

Claims

1. A method for assigning spreading sequences to signals of an OFDM transmission network, comprising the steps of:

establishing a transmission channel that includes a plurality of signals operating on different sub-carrier frequencies;

assigning at least one spreading sequence from a set of spreading sequences to data items to be transmitted on a signal in order to establish a sub-set of spreading sequences which includes less than all the spreading sequences; and

minimizing the interference between the spreading sequences by dynamically varying the sub-set of assigned spreading sequences.

2. A method according to claim 1 wherein the signal includes a signal transmitted from the antenna of a wireless OFDM transmission network.

3. A method according to claim 1 wherein the signal includes a signal transmitted from a base station to a mobile station.

4. A method according to claim 1 wherein the signal includes a signal transmitted from a mobile station to a base station.

5. A method according to claim 1 wherein the spreading sequences include Walsh-Hadamard sequences.

6. A method according to claim 1 wherein the spreading sequences include Gold sequences.

7. A method according to claim 1 wherein the spreading sequences include Kasami sequences.

8. A method according to claim 1 wherein a user is assigned to a signal operating on a specified sub-carrier frequency.

9. A method according to claim 1 wherein a cost function is used to minimize the interference.

10. A method according to claim 1 which further includes the step of using equalization to further minimize the interference.

11. A transmitter for an OFDM transmission network, comprising:

means for generating data items for a user;

means for multiplying the data items by at least one spreading sequence for each user;

means for modulating the spread sequenced data items onto a transmission channel that includes a plurality of signals operating on different sub-carrier frequencies;

wherein the data items of each user are assigned at least one spreading sequence from a set of spreading sequences to establish a sub-set of spreading sequences that are dynamically varied to minimize the interference between the signals operating on the sub-carrier frequencies.