System and method using adaptive antennas to selectively reuse common physical channel timeslots for dedicated channels

• US 20050190729A1
• Filed: 04/19/2005
• Published: 09/01/2005
• Est. Priority Date: 02/11/2003
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Marinier, Paul, Roy, Vincent
• Granted Patent: US 7,096,032 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A method and communication system (e.g., a time-division duplex (TDD) system) that uses adaptive antennas at the base stations to monitor metrics associated with the quality of one or more common physical channel (CPCH) timeslots, so as to determine whether to reuse some or all of the CPCH timeslots to transmit a dedicated physical channel (DPCH). If it is determined to reuse some or all of the CPCH timeslots, an additional determination is made as to what limit to apply on the DPCH transmission powers. Adaptive antennas may be used at the base stations to allow the system to reuse some or all of the CPCH timeslots to transmit DPCH, thus improving the overall capacity of the system while maintaining the CPCH coverage and quality at a desired level throughout the system.

Claims

1. In a wireless communication system including a plurality of cells, each cell having a plurality of angular sections, a method of reusing common physical channel (CPCH) timeslots to transmit dedicated physical channel (DPCH) signals, the method comprising:

(a) tagging each CPCH timeslot as being aggressive or non-aggressive;

(b) increasing by a predetermined amount the power of a DPCH signal transmitted for each CPCH timeslot that is tagged as being non-aggressive and the power is below a predetermined maximum power level;

(c) monitoring the metrics associated with the quality of the CPCH timeslot; and

(d) for each angular section of each cell associated with a degradation of CPCH quality, determining the respective neighboring cells, reducing the maximum power level for the CPCH timeslots in the neighboring cells associated with the degradation of CPCH quality, and tagging the neighboring cells as being aggressive for the CPCH timeslots associated with the degradation of CPCH quality.

2. The method of claim 1 further comprising:

(e) assigning a predetermined number of downlink timeslots;

(f) assigning a predetermined number of uplink timeslots; and

(g) assigning a predetermined number of CPCH timeslots.

3. The method of claim 2 wherein the number of CPCH timeslots is between one and the number of downlink timeslots.

4. The method of claim 1 wherein the communication system is a time-division duplex (TDD) system and the cells are TDD cells.

5. In a wireless communication system, a method of reusing the common physical channel (CPCH) timeslots to transmit dedicated physical channel (DPCH) signals at a power level that does not exceed a maximum power level, the system including (i) a plurality of cells, each cell having a plurality of angular sections;

(ii) a plurality of wireless transmit/receive units (WTRUs);

(iii) a radio access network (RAN) for collecting metrics associated with the quality of the CPCH timeslots and received power measured by said WTRUs;

(iv) a plurality of base stations which transmit CPCH signals over a plurality of timeslots, said base stations having adaptive antennas operating in respective ones of said cells, each base station being in communication with respective ones of said WTRUs; and

(v) a database which associates the cells with the adaptive antennas of the base stations, the method comprising;

(a) the RAN determining that the communication system has a stable distribution of CPCH metrics for each angular section of each cell; and

(b) tagging, in the database, each CPCH timeslot as being aggressive or non-aggressive.

6. The method of claim 5 further comprising:

(c) increasing by a predetermined amount the power of a DPCH signal transmitted by the base station in each CPCH timeslot that is tagged as being non-aggressive and the power is below a predetermined maximum power level;

(d) monitoring the metrics associated with the quality of the CPCH timeslot; and

(e) for each angular section of each cell associated with a degradation of CPCH quality, determining the respective neighboring cells, reducing the maximum power level for the CPCH timeslots in the neighboring cells associated with the degradation of CPCH quality, and tagging, in the database, the neighboring cells as being aggressive for the CPCH timeslots associated with the degradation of CPCH quality.

7. The method of claim 6 further comprising:

(f) assigning a predetermined number of downlink timeslots;

(g) assigning a predetermined number of uplink timeslots; and

(h) assigning a predetermined number of CPCH timeslots.

8. The method of claim 7 wherein the number of CPCH timeslots is between one and the number of downlink timeslots.

9. The method of claim 6 further comprising repeating steps (c)-(e) until all of the CPCH slots are tagged in the database as being aggressive or are designated to transmit DPCH signals at the maximum power level.

10. The method of claim 5 wherein the communication system is a time-division duplex (TDD) system and the cells are TDD cells.

11. A wireless communication system which reserves common physical channel (CPCH) timeslots, the system comprising:

(a) a database in which each CPCH timeslot is tagged as being aggressive or non-aggressive;

(b) a plurality of cells, each cell having a plurality of angular sections;

(c) a processor in communication with the database; and

(d) a process running on the processor for monitoring the metrics associated with the quality of the CPCH timeslot, wherein for each angular section of each cell associated with a degradation of CPCH quality, the respective neighboring cells are determined, the maximum power level for the CPCH timeslots in the neighboring cells associated with the degradation of CPCH quality is reduced, and in the database, the CPCH timeslots in the neighboring cells associated with the degradation of CPCH quality are tagged as being aggressive.

12. The system of claim 11 further comprising:

(e) a plurality of wireless transmit/receive units (WTRUs);

(f) a radio access network (RAN) for collecting metrics associated with the quality of the CPCH timeslots and received power measured by the WTRUs; and

(g) a plurality of base stations which transmit CPCH signals over a plurality of timeslots, said base stations having adaptive antennas operating in respective ones of said cells, each base station being in communication with respective ones of said WTRUs.

13. The system of claim 11 wherein the CPCH timeslots are reserved to transmit broadcast channel (BCH) signals.

14. The system of claim 11 wherein the CPCH timeslots are reused to transmit dedicated physical channel (DPCH) signals at a power level that does not exceed a maximum power level

15. A wireless communication system including a plurality of cells and a database, each cell having a plurality of angular sections, the system for reusing common physical channel (CPCH) timeslots to transmit dedicated physical channel (DPCH) signals, the system comprising:

(a) means for tagging in the database each CPCH timeslot as being aggressive or non-aggressive;

(b) means for increasing by a predetermined amount the power of a DPCH signal transmitted for each CPCH timeslot that is tagged as being non-aggressive and the power is below a predetermined maximum power level;

(c) means for monitoring the metrics associated with the quality of the CPCH timeslot;

(d) means for determining the respective neighboring cells for each angular section of each cell associated with a degradation of CPCH quality;

(e) means for reducing the maximum power level for the CPCH timeslots in the neighboring cells associated with the degradation of CPCH quality; and

(f) means for tagging in the database the CPCH timeslots in the neighboring cells associated with the degradation of CPCH quality as being aggressive.

16. The system of claim 15 wherein the system is a time-division duplex (TDD) system and the cells are TDD cells.