Method employed by a base station for controlling initial power ramp-up using short codes

• US 6,839,567 B2
• Filed: 03/26/2003
• Issued: 01/04/2005
• Est. Priority Date: 06/27/1996
• Status: Expired due to Term

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Lomp, Gary R., Ozluturk, Fatih M.
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): LE, LANA N
• Application Number:
  US10/400,343
• Publication Number:
  US 20030199285A1
• Time in Patent Office: 650 Days
• Field of Search: 455/522, 455/63.1, 455/69, 455/67.1, 455/403, 455/67.4, 370/335, 375/205, 375/130, 375/200
• US Class Current: 455/522
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/70753 Partial phase search
• CPC Class Codes: H04B 1/70755 Setting of lock conditions, e.g. threshold
• CPC Class Codes: H04B 1/70758 Multimode search, i.e. using multiple search strategies
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04B 1/708 Parallel implementation
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 2201/7071 with dynamic control of receiver resources
• 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: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 52/60 using different transmission rates for TPC commands

Abstract

A base station for controlling transmission power during the establishment of a communication channel utilizes the reception of a short code during initial power ramp-up. The short code is a sequence for detection by the base station which has a much shorter period than a conventional access code. The ramp-up starts from a power level that is lower than the required power level for detection by the base station. The power of the short code is quickly increased until the signal is detected by the base station. Once the base station detects the short code, it transmits an indication that the short code has been detected.

Claims

1. A method employed by a base station for controlling transmission power during the establishment of communications between a base station and another communicating unit, comprising:

detecting a short code having an initial predetermined power level, which is repeatedly sent to the base station at increasing power levels;

transmitting a power control signal when the short code having sufficient power for detection is received; and

receiving an access signal which is longer than and includes the short code and having a power level established upon receipt of said power control signal.

2. The method of claim 1 wherein said initial predetermined power level is lower than a power level required for detection by said base station.

3. The method of claim 1 further comprising determining an initial phase of the access code by initially searching only one phase out of a short code length portion of the access code.

4. The method of claim 3 further comprising transmitting an acknowledgment when the correct phase of the access code is detected.

5. The method of claim 3 further comprising performing a subsequent search by searching every phase when a correct phase has not been detected after a given interval.

6. The method of claim 5 wherein said interval is measured starting at a beginning of the initial search.

7. The method of claim 1 wherein the control signal is generated when the correct phase of the short code is detected.

8. The method of claim 1 wherein the established power level is changed by a predetermined amount.