Code division multiple access (CDMA) communication system

• US 6,157,619 A
• Filed: 09/22/1999
• Issued: 12/05/2000
• Est. Priority Date: 06/30/1995
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Jacques, Alexander, Ozluturk, Fatih, Kowalski, John, Lomp, Gary
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Elallam, Ahmed
• Application Number:
  US09/401,628
• Time in Patent Office: 440 Days
• Field of Search: 370/208, 370/209, 370/249, 370/252, 370/319, 370/320, 370/328, 370/329, 370/332, 370/333, 370/335, 370/342, 370/479, 370/491, 370/500, 375/200, 375/206, 375/208, 375/354, 455/31.1, 455/36.1, 455/67.1, 455/69, 455/70, 455/226.1, 455/226.3, 455/436, 455/442, 455/522, 455/561
• US Class Current: 370/252
• 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 1/708 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 1/7103 the interference being multiple access 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 1/7183 Synchronisation
• 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 7/2637 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 13/10 : Code generation
• CPC Class Codes: H04J 2013/0037 : Multilevel codes
• 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 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: H04W 24/08 : Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 28/22 : Negotiating communication rate
• CPC Class Codes: H04W 36/06 : Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 52/0238 : where the received signal is an unwanted signal, e.g. interference or idle signal
• 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 52/26 : 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 52/346 : 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 52/362 : 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 52/60 : using different transmission rates for TPC commands
• CPC Class Codes: H04W 72/0466 : the resource being a scrambling code
• CPC Class Codes: H04W 88/021 : adapted for Wireless Local Loop operation
• CPC Class Codes: H04W 88/08 : Access point devices
• CPC Class Codes: H04W 88/181 : Transcoding devices; Rate adaptation devices
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

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 multiple access, base station test apparatus for acquiring and providing a plurality of system parameters of a Code Division Multiple Access (CDMA) communication system, the base station test system receiving a forward telecom signal, and processing the forward telecom signal for transmission as a forward CDM signal to a subscriber unit (SU), the apparatus comprising:

receiving means for receiving the forward telecom signal, and converting the telecom signal into a forward information signal and a forward call request signal;

master modem processing means including

a) means for providing a global pilot code signal and at least one broadcast channel signal,

b) means for combining, responsive to the forward call request, the forward call request and a message pilot identifier with the at least one broadcast channel signal, wherein the at least one broadcast channel signal is synchronized to the global pilot code signal; and

c) means for measuring and storing master modem system information,

slave modem processing means for providing the forward information signal as a modulated forward CDM message signal, the slave modem processing means including

a) means for measuring and for storing slave modem system information, and;

b) forward processing means for modulating the forward information signal with one of a plurality of forward message code signals, the one of the plurality of forward message code signals corresponding to the message pilot identifier, to provide the modulated forward CDM signal, wherein the plurality of forward message code signals are synchronized to the global pilot code signal; and

system control means, coupled to the master modem processing means and the slave modem processing means, for retrieving the stored master modem system information and the stored slave modem system information, the system control means including means for processing, responsive to a request signal, the stored master modem system information and the stored slave modem system information into a data record signal having the plurality of system parameters.

2. The multiple access, base station test apparatus as recited in claim 1, further comprising transmission means for converting a reverse information signal and a reverse call request signal into a reverse telecom signal, and wherein:

the base station test apparatus includes means for receiving a reverse Code Division Multiplex (CDM) signal from the SU;

the master modem processing means further includes;

d) means for demodulating the reverse CDM signal to receive an access pilot code signal and at least one access channel signal, the access pilot code signal and the at least one access channel signal being synchronized to the global pilot code signal, and

e) means for extracting a reverse call request signal corresponding to the SU from the at least one access channel signal; and

the slave modem processing means includes;

c) means for demodulating the reverse CDM signal to provide the reverse information signal, and

d) reverse processing means for receiving the reverse CDM signal and correlating the reverse CDM signal with one of a plurality of reverse message code signals, the plurality of reverse message code signals being synchronized to the global pilot code signal and the one of the reverse message code signals corresponding to the message pilot identifier, to demodulate the reverse CDM signal to recover the reverse information signal.

3. The multiple access, spread spectrum base station test apparatus as recited in claim 2, further including a call-processing interface comprising:

means for receiving a forward telephone line signal and converting the forward telephone line signal into a forward information signal and a user identification value corresponding to the SU;

means for creating a forward call request signal; and

means for providing the forward information signal, the forward call request signal and the user identification signal as the forward telecom signal.

4. The multiple access spread-spectrum base station test apparatus as recited in claim 3, wherein the call-processing interface further comprises:

means for receiving the reverse telecom signal;

means for providing, responsive to the reverse call request signal, the reverse information signal and the call request signal; and

means for converting the reverse information signal into a reverse telephone line signal.

5. The multiple access, spread spectrum base station test apparatus as recited in claim 2, wherein the slave modem processing means is one of a plurality of slave modem processing means and the system control means provides a respective channel assignment signal to each of the plurality of slave modem processing means, the apparatus further comprising:

assignment means, responsive to the channel assignment signal, for coupling the forward information signal from the receiving means to a respective one of the plurality of slave modem processing means, and for coupling the reverse information signal from one of the plurality of slave modem processing means to the transmission means.

6. The multiple-access spread-spectrum base station test apparatus as recited in claim 1, wherein the plurality of system parameters includes at least one of a value representing a total system interference noise power, a value representing a total number of calls, a value representing an average number calls per unit time, a value representing an average time to synchronize to a reverse CDM signal, a value representing a transmit power level of the SU, a value representing an automatic gain control (AGC) signal value for the SU, a value representing an AGC signal value received by the base station test apparatus, a value representing a plurality of acquisition and tracking parameters for the reverse CDM signal and a value representing a number of dropped calls.

7. The multiple access spread-spectrum base station test apparatus as recited in claim 2, further comprising:

Radio Frequency (RF) transmitter means, connected to the master modem processing means and the slave modem processing means, for combining the forward CDM signal, the global pilot code signal and at least one broadcast channel signal into a transmit CDM signal, and for modulating a first carrier signal with the transmit CDM signal and for transmitting the modulated first carrier signal through an RF communication channel; and

RF receiver means for receiving a second carrier signal modulated by the reverse CDM signal, and for demodulating the modulated second carrier signal to provide the reverse CDM signal.

8. The multiple access spread-spectrum base station test apparatus as recited in claim 1, wherein the system control means further includes memory means for storing the master modem system information and the slave modem system information, the apparatus further comprising remote terminal means including:

a) input means for receiving a plurality of user commands;

b) processing means for translating each one of the plurality of user commands into the request signal;

c) means for receiving the data record signal;

d) display control means for processing the data record signal into a display format; and

e) display means for displaying the plurality of system parameters contained in the data record signal in the display format.