Bearer channel modification system for a code division multiple access (CDMA) communication system

• US 6,215,778 B1
• Filed: 10/23/1997
• Issued: 04/10/2001
• Est. Priority Date: 06/30/1995
• Status: Expired due to Term

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Jacques, Alexander, Ozluturk, Fatih, Kowalski, John, Lomp, Gary, Silverberg, Avi, Marra, Alexander, Luddy, Michael, Regis, Robert
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): YAO, KWANG BIN
• Application Number:
  US08/956,740
• Time in Patent Office: 1,265 Days
• Field of Search: 370/310, 370/318, 370/320, 370/328, 370/329, 370/335, 370/342, 370/465, 370/468, 370/477, 370/441, 370/479, 370/503, 370/515, 375/140, 375/146, 375/147, 375/354, 375/367
• US Class Current: 370/335
• CPC Class Codes: G06F 13/374 using a self-select method with individual priority code comparator
• CPC Class Codes: H03H 17/0226 comprising look-up tables
• CPC Class Codes: H03H 17/06 Non-recursive filters
• 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 1/709 Correlator structure
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04B 1/711 the interference being multi-path interference
• 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 13/0048 : Walsh
• CPC Class Codes: H04J 13/0077 : Multicode, e.g. multiple codes assigned to one user
• CPC Class Codes: H04J 13/10 : Code generation
• CPC Class Codes: H04J 13/107 : by concatenation
• CPC Class Codes: H04J 13/12 : Generation of orthogonal codes
• CPC Class Codes: H04J 13/16 : Code allocation
• CPC Class Codes: H04J 2013/0037 : Multilevel codes
• CPC Class Codes: H04L 1/0001 : Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/004 : by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/0042 : Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0047 : Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• CPC Class Codes: H04L 1/0054 : Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/0059 : Convolutional codes
• 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 52/04 : TPC
• CPC Class Codes: H04W 52/08 : Closed loop power control
• CPC Class Codes: H04W 52/143 : Downlink 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 52/241 : taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/245 : taking into account received signal strength
• CPC Class Codes: H04W 52/247 : where the output power of a terminal is based on a path parameter sent by another terminal
• CPC Class Codes: H04W 52/26 : using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/262 : taking into account adaptive modulation and coding [AMC] scheme AMC per se H04L1/0001
• 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 52/346 : 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 52/367 : 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
• CPC Class Codes: Y02D 10/00 : Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A multiple access, spread-spectrum communication system processes a plurality of information signals received by a Radio Carrier Station (RCS) over telecommunication lines for simultaneous transmission over a radio frequency (RF) channel as a code-division-multiplexed (CDM) signal to a group of Subscriber Units (SUs). The RCS receives a call request signal that corresponds to a telecommunication line information signal, and a user identification signal that identifies a user to receive the call. The RCS includes a plurality of Code Division Multiple Access (CDMA) modems, one of which provides a global pilot code signal. The modems provide message code signals synchronized to the global pilot signal. Each modem combines an information signal with a message code signal to provide a CDM processed signal. The RCS includes a system channel controller is coupled to receive a remote call. An RF transmitter is connected to all of the modems to combine the CDM processed signals with the global pilot code signal to generate a CDM signal. The RF transmitter also modulates a carrier signal with the CDM signal and transmits the modulated carrier signal through an RF communication channel to the SUs. Each SU includes a CDMA modem which is also synchronized to the global pilot signal. The CDMA modem despreads the CDM signal and provides a despread information signal to the user. The system includes a closed loop power control system for maintaining a minimum system transmit power level for the RCS and the SUs, and system capacity management for maintaining a maximum number of active SUs for improved system performance.

Claims

1. A bearer channel modification system for a multiple access spread-spectrum communication system including a plurality of information signals each having several different channel rates which information signals are transmitted as a plurality of message code channels over an Radio Frequency (RF) channel as a Code Division Multiplexed (CDM) signal, each of the plurality of message code channels being able to convey information at a predetermined information channel rate, the system comprising

means for providing a plurality of call type signals corresponding to the information signal rates for the information signals;

a transmitter including a first information channel mode modification means responsive to the call type signal for changing the information signal from a first one of the message code signals to a second one of the message code signals which second message code signal has a different information channel rate than the first message code signal; and

a receiver including a second information channel mode modification means responsive to the call type signal for changing a received information signal from the first message code signal to the second message code signal to receive the information signal at the different information channel rate.

2. A bearer channel modification system according to claim 1 wherein the transmitter further includes means for sequentially a) sending the message data combined with the first message code signal to the substantial exclusion of the second message code signal, b) concurrently sending the message data combined with the first message code signal and the message data combined with the second message code signal and c) sending the message data combined with the second message code signal to the substantial exclusion of the first message code signal.

3. A bearer channel modification system according to claim 1 wherein the transmitter further includes:

means for synchronizing the transmitter to the receiver on a sub-epoch boundary;

means for sending the message signal combined with the first message code signal prior to the sub-epoch boundary and for sending the message signal combined with the second message code signal to the substantial exclusion of the first message code signal subsequent to the sub-epoch boundary.

4. A multiple access spread-spectrum communication system for dynamically changing a transmission rate of a plurality of information signals received simultaneously over telecommunication lines by a base station and transmitted to a subscriber through a plurality of spread-spectrum message channels, the system comprising

a) a base station, connected to a remote call-processor which provides a call type signal identifying an information signal rate of the respective information signal and a conversion method for the respective information signal;

comprising;

a system channel controller which assigns each of the information signals and call type signals to a respective spread-spectrum message channel;

first information channel mode modification means connected to the system channel controller and responsive to the call type signal for changing the combination of the respective information signal from one spread-spectrum message channel to another pre-determined spread-spectrum message channel which supports a different information channel rate; and

b) a subscriber unit comprising;

a plurality of despreading means, each of the despreading means for recovering a respective one of the information signals and a respective one of the call type signals from a respective one of the spread-spectrum message channels;

second information channel mode modification means responsive to the call type signal for selectively assigning one of the despreading means to a respective one of the spread spectrum message channels which supports the different information rate; and

a signal conversion means responsive to the call type signal for selectively converting the despread information signal into a digital data signal.

5. A bearer channel modification system for a multiple access spread-spectrum communication system including a plurality of information signals each having a respective rate, the system comprising

a plurality of message code channels, each of the channels being able to convey information at a respective predetermined information channel rate, wherein an information signal is transmitted as at least one message code channel as a Code Division Multiplexed (CDM) signal

means for providing a plurality of call type signals corresponding to the information signal rates for the information signals;

a transmitter including a first information channel mode modification means responsive to the call type signal for changing the information signal from a first one of the message code signals to a second one of the message code signals which second message code signal has a respective information channel rate; and

a receiver including a second information channel mode modification means responsive to the call type signal for changing a received information signal from the first message code signal to the second message code signal to receive the information signal at the respective information channel rate.

6. A bearer channel modification system according to claim 5 further including:

means, coupled to the transmitter, for changing the predetermined information channel rate of at least one of the message code channels from a first rate to a second rate; and

means, coupled to the receiver and responsive to a signal provided by the transmitter for conditioning the receiver to receive the information signal provided via the one message code channel at the first rate before the predetermined information channel rate is changed and at the second rate after the predetermined information channel rate is changed.