Initial power control for spread-spectrum communications

• US 20050094604A1
• Filed: 11/12/2004
• Published: 05/05/2005
• Est. Priority Date: 06/30/1995
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Lomp, Gary R., Ozluturk, Fatih M., Kowalski, John
• Granted Patent: US 7,535,874 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H03H 17/0226 comprising look-up tables
• CPC Class Codes: H03H 17/0254 Matched filters
• CPC Class Codes: H03H 17/06 Non-recursive filters
• CPC Class Codes: H03H 17/0607 comprising a ROM addressed by the input data signals
• CPC Class Codes: H03H 2218/06 Multiple-input, multiple-output [MIMO]; Multiple-input, single-output [MISO]
• 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 1/70754 Setting of search window, i.e. range of code offsets to be searched H04B1/70758 takes precedence
• 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 1/7085 using a code tracking loop, e.g. a delay-locked loop
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 1/712 Weighting of fingers for combining, e.g. amplitude control or phase rotation using an inner loop
• 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 2201/70707 : Efficiency-related aspects
• 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: H04B 7/2637 : for logical channel control
• CPC Class Codes: H04B 7/264 : for data rate control
• CPC Class Codes: H04J 13/00 : Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04J 13/004 : Orthogonal
• CPC Class Codes: H04J 13/0077 : Multicode, e.g. multiple codes assigned to one user
• CPC Class Codes: H04L 1/0059 : Convolutional codes
• CPC Class Codes: H04L 1/1692 : Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts
• CPC Class Codes: H04L 2001/0094 : Bus
• CPC Class Codes: H04L 2027/003 : at baseband only
• CPC Class Codes: H04L 2027/0053 : Closed loops
• CPC Class Codes: H04L 25/0212 : of impulse response
• CPC Class Codes: H04L 27/206 : using a pair of orthogonal carriers, e.g. quadrature carriers
• CPC Class Codes: H04L 27/2332 : using a non-coherent carrier
• CPC Class Codes: H04L 5/1446 : of transmission speed
• CPC Class Codes: H04N 1/00912 : Arrangements for controlling a still picture apparatus or components thereof not otherwise provided for
• CPC Class Codes: H04N 1/3333 : during transmission, input or output of the picture signal; within a single document or page
• CPC Class Codes: H04N 2201/3335 : Speed or rate
• CPC Class Codes: H04W 52/08 : Closed loop power control
• CPC Class Codes: H04W 52/146 : Uplink power control
• CPC Class Codes: H04W 52/24 : using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/26 : using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/322 : Power control of broadcast channels
• CPC Class Codes: H04W 52/325 : Power control of control or pilot channels
• CPC Class Codes: H04W 52/343 : taking into account loading or congestion level
• 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 52/362 : Aspects of the step size
• CPC Class Codes: H04W 52/367 : Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/44 : in connection with interruption of transmission
• CPC Class Codes: H04W 52/50 : at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 52/52 : using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: H04W 52/54 : Signalisation aspects of the TPC commands, e.g. frame structure
• CPC Class Codes: H04W 52/60 : using different transmission rates for TPC commands

Abstract

A code-division-multiple-access (CDMA) system employing spread-spectrum modulation. The CDMA system has a base station, and a plurality of subscriber units. The signals transmitted between the base station and subscriber unit use spread-spectrum modulation. The system and method transmits from the base station, a synchronization channel having a chip-sequence signal used by the plurality of subscriber units for synchronization. A first subscriber unit receives the synchronization channel, and determines timing from the synchronization channel. In order to initiate communications with the base station, the first subscriber unit transmits an access signal. The access signal has a plurality of power levels, which typically ramp up. The base station receives the access signal at a particular-power level. The base station then transmits to the first subscriber unit an acknowledgment signal. The first subscriber unit receives the acknowledgment signal, and transmits to the base station, a spread-spectrum signal.

Claims

1. A method of using a code division multiple access (CDMA) system including at least one base station in communication with a plurality of subscriber units, the method comprising:

(a) the base station transmitting a synchronization channel having a code signal used for synchronization by the plurality of subscriber units;

(b) a first one of the subscriber units receiving and acquiring the synchronization channel;

(c) the first subscriber unit synchronizing to the synchronization channel;

(d) the first subscriber unit determining timing from the synchronization channel;

(e) the first subscriber unit transmitting an access signal having a plurality of power levels;

(f) the base station detecting the access signal and, in response, transmitting an acknowledgement signal to the first subscriber unit; and

(g) the first subscriber unit receiving the acknowledgment signal and, in response, transmitting a spread-spectrum signal with data to the base station.

2. The method of claim 1 wherein the first subscriber unit transmits the access signal using spread-spectrum modulation synchronized to the timing from the synchronization channel determined by the first subscriber unit in step (d).

3. A code division multiple access (CDMA) system comprising:

(a) at least one base station; and

(b) a plurality of subscriber units in communication with the base station, wherein;

(i) the base station transmits a synchronization channel having a code signal used for synchronization by the plurality of subscriber units;

(ii) a first one of the subscriber units receives and acquires the synchronization channel;

(iii) the first subscriber unit synchronizes to the synchronization channel;

(iv) the first subscriber unit determines timing from the synchronization channel;

(v) the first subscriber unit transmits an access signal having a plurality of power levels;

(vi) the base station detects the access signal and, in response, transmits an acknowledgement signal to the first subscriber unit; and

(vii) the first subscriber unit receives the acknowledgment signal and, in response, transmits a spread-spectrum signal with data to the base station.

4. The system of claim 3 wherein the first subscriber unit transmits the access signal using spread-spectrum modulation synchronized to the timing from the synchronization channel determined by the first subscriber unit.

5. A method of using a code division multiple access (CDMA) system including at least one base station in communication with a plurality of subscriber units, the method comprising:

(a) the base station transmitting a synchronization channel having a code signal used for synchronization by the plurality of subscriber units;

(b) a first one of the subscriber units synchronizing to the synchronization channel and determining timing from the synchronization channel;

(c) the first subscriber unit transmitting an access signal based on the timing determined in step (b);

(d) the base station detecting the access signal and, in response, transmitting an acknowledgement signal to the first subscriber unit; and

(e) the first subscriber unit receiving the acknowledgment signal and, in response, transmitting a spread-spectrum signal with data to the base station.

6. The method of claim 5 wherein the first subscriber unit transmits the access signal using spread-spectrum modulation synchronized to the timing from the synchronization channel determined by the first subscriber unit in step (b).

7. A code division multiple access (CDMA) system comprising:

(a) at least one base station; and

(b) a plurality of subscriber units in communication with the base station, wherein;

(i) the base station transmits a synchronization channel having a code signal used for synchronization by the plurality of subscriber units;

(ii) a first one of the subscriber units synchronizes to the synchronization channel and determines timing from the synchronization channel;

(iii) the first subscriber unit transmits an access signal based on the timing determined by the first subscriber unit;

(iv) the base station detects the access signal and, in response, transmits an acknowledgement signal to the first subscriber unit; and

(v) the first subscriber unit receives the acknowledgment signal and, in response, transmits a spread-spectrum signal with data to the base station.

8. The system of claim 7 wherein the first subscriber unit transmits the access signal using spread-spectrum modulation synchronized to the timing from the synchronization channel determined by the first subscriber unit.

9. A code-division-multiple-access (CDMA) system comprising:

(a) means for transmitting, using spread-spectrum modulation, a synchronization channel having a code signal used for synchronization;

(b) means for receiving the synchronization channel;

(c) means for determining timing from the synchronization channel;

(d) means for transmitting, using spread-spectrum modulation, an access signal, the access signal having a plurality of power levels;

(e) means for detecting the access signal;

(f) means for transmitting an acknowledgment signal in response to detecting the access signal;

(g) means for receiving the acknowledgment signal; and

(h) means for transmitting a spread-spectrum signal with data in response to receiving the acknowledgment signal.

10. The method of claim 9 further comprising means for transmiting the access signal using spread-spectrum modulation synchronized to the timing from the synchronization channel determined by the determining means.