Asymmetrical forward/reverse transmission bandwidth

• US 6,728,225 B1
• Filed: 02/10/2000
• Issued: 04/27/2004
• Est. Priority Date: 02/10/2000
• Status: Expired due to Term

• Current Assignee: Pantech Wireless, LLC (Ideahub, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Ozluturk, Fatih
• Primary Examiner(s): Nguyen, Steven H. D
• Assistant Examiner(s): SHAND, ROBERTA A
• Application Number:
  US09/501,865
• Time in Patent Office: 1,538 Days
• Field of Search: 370/320, 370/328, 370/335, 370/342, 370/441, 370/468, 370/203, 370/206, 370/209, 455/422, 455/445, 455/446, 455/450, 455/464, 375/140, 375/141-145
• US Class Current: 370/320
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2001/6904 using code hopping
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04B 7/2668 Arrangements for Wireless Code-Division Multiple Access [CDMA] System Synchronisation, for code acquisition H04B1/7075, for code tracking H04B1/7085
• CPC Class Codes: H04L 2012/6475 N-ISDN, Public Switched Telephone Network [PSTN]
• CPC Class Codes: H04L 43/028 by filtering
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A wireless communications system employs code-division multiple access information transmission techniques where the uplink and downlink transmission bandwidths are unequal. The higher bandwidth is an integer multiple of the lower bandwidth. The present system requires a base station and a subscriber unit to have two pseudo-random code generators which can be clocked separately. Alignment of the uplink and downlink pseudo-random spreading codes is achieved by truncating the code sequence for the lower speed link at the conclusion of a complete code sequence for the higher speed link.

Claims

1. A communication system utilizing spreading code sequences in both uplink and downlink data paths, the system comprising:

a downlink data path having a first bandwidth allocated thereto for sending a first repetitious code sequence at a first data rate;

an uplink data path having a second bandwidth allocated thereto for sending a second repetitious code sequence at a second data rate, the second bandwidth being larger than the first bandwidth;

a first generator in communication with the downlink path, the first generator outputting the first code sequence;

a second generator in communication with the uplink path, the second generator outputting the second code sequence, wherein the first code sequence is truncated each time the second code sequence is repeated.

2. The system of claim 1 wherein the second bandwidth is an integer multiple of the first bandwidth.

3. The system of claim 1 wherein the system is a code-division multiple access (CDMA) communication system.

4. A communication system utilizing spreading code sequences in both uplink and downlink data paths, the system comprising:

a downlink data path having a first bandwidth allocated thereto for sending a first repetitious code sequence at a first data rate;

an uplink data path having a second bandwidth allocated thereto for sending a second repetitious code sequence at a second data rate, the first bandwidth being larger than the second bandwidth;

a first generator in communication with the downlink path, the first generator outputting the first code sequence;

a second generator in communication with the uplink path, the second generator outputting the second code sequence, wherein the second code sequence is truncated each time the first pseudo code sequence is repeated.

5. The system of claim 4 wherein the first bandwidth is an integer multiple of the second bandwidth.

6. The system of claim 4 wherein the system is a code-division multiple access (CDMA) communication system.

7. A communication system utilizing spreading code sequences in both uplink and downlink data paths, the system comprising:

a base station;

a subscriber unit in communication with the base station via (i) a downlink data path having a first bandwidth allocated thereto for sending a first repetitious code sequence at a first data rate, and (ii) an uplink data path having a second bandwidth allocated thereto for sending a second repetitious code sequence at a second data rate, the second bandwidth being larger than the first bandwidth;

a first generator in communication with the downlink path, the first generator outputting the first code sequence;

a second generator in communication with the uplink path, the second generator outputting the second code sequence, wherein the first code sequence is truncated each time the second code sequence is repeated.

8. The system of claim 7 wherein the first bandwidth is an integer multiple of the second bandwidth.

9. The system of claim 7 wherein the system is a code-division multiple access (CDMA) communication system.

10. A communication system utilizing spreading code sequences in both uplink and downlink data paths, the system comprising:

a base station;

a subscriber unit in communication with the base station via (i) a downlink data path having a first bandwidth allocated thereto for sending a first repetitious code sequence at a first data rate, and (ii) an uplink data path having a second bandwidth allocated thereto for sending a second repetitious code sequence at a second data rate, the first bandwidth being larger than the second bandwidth;

a first generator in communication with the downlink path, the first generator outputting the first code sequence;

a second generator in communication with the uplink path, the second generator outputting the second code sequence, wherein the second code sequence is truncated each time the first code sequence is repeated.

11. The system of claim 10 wherein the second bandwidth is an integer multiple of the first bandwidth.

12. The system of claim 10 wherein the system is a code-division multiple access (CDMA) communication system.

13. A communication method utilizing spreading code sequences in both uplink and downlink data paths, the method comprising:

assigning a first bandwidth to a downlink data path;

assigning a second bandwidth to an uplink data path, the second bandwidth being larger than the first bandwidth;

applying a first repetitious code sequence to transmit data over the downlink path at a first data rate;

applying a second repetitious code sequence to transmit data over the uplink path at a second data rate; and

truncating the first code sequence each time the second code sequence is repeated.

14. The method of claim 13 wherein the first bandwidth is an integer multiple of the second bandwidth.

15. A communication method utilizing spreading code sequences in both uplink and downlink data paths, the method comprising:

assigning a first bandwidth to a downlink data path;

assigning a second bandwidth to an uplink data path, the first bandwidth being larger than the second bandwidth;

applying a first repetitious code sequence to transmit data over the downlink path at a first data rate;

applying a second repetitious code sequence to transmit data over the uplink path at a second data rate; and

truncating the second code sequence each time the first code sequence is repeated.

16. The method of claim 15 wherein the second bandwidth is an integer multiple of the first bandwidth.