Interdigital Technology Corporation

Robert T Regis

Fatih M Ozluturk

John Michael Kowalski

Gary R Lomp

Alexander M Jacques

Michael J Luddy

Avi Silverberg

Alexander Marra

Leonid L Kazakevich

Stephen G Dick

Jeffrey S Polan

Richard Turner

James D Nolan

Fred M Schreider

Fryderyk Tyra

Michael Luddy

The present invention provides a base station architecture that is modular in configuration, lowering the initial cost of implementing a new CDMA telecommunication system for a defined geographical region while allowing for future capacity. The scalable architecture is assembled from a digital base station unit that is configured to support a plurality of simultaneous wireless calls connecting to a conventional public switched telephone network. For initial startup, two base station units are deployed for redundancy in case of a single failure. Additional base station units may be added when the need arises for extra traffic capacity. If sectorization is required, the base station units may be directionally oriented. Coupled to and remote from each base station unit are two amplified antenna modules that contain an omni-directional or an external directional antenna, a high power RF amplifier for transmitted frequencies and a low noise amplifier for received frequencies. A separate power supply module capable of supporting two base station units provides continued service in the event of a mains power outage.

Modular base station with variable communication capacity

An efficient, multichannel filter for CDMA modems permits multiple serial, digital bit streams to be filtered by digital signal processing techniques including sample weighting and summing functions. Each individual channel may have custom weighting coefficients or weighting coefficients common for all channels. If the weighting coefficients are by adaption, the same approach may be taken. The multichannel FIR filter is implemented with no multipliers and a reduction in the number of adders. To increase the speed of operation, the filter structure utilizes look-up tables storing the weighting coefficients. The invention can be embodied as either as a field programmable gate array or an application specific integrated circuit. The use of look-up tables saves significant chip resources.

Efficient multichannel filtering for CDMA modems

A communication system emulator digitally emulates a plurality of signal impairments created by the transmitter and receiver components and communication medium in a typical communication system, for use in evaluating and refining modem design. A variety of linear and non-linear distortion characteristics are impressed on baseband signals between modulators and demodulators to evaluate and refine modem performance without requiring transmission frequency components or communication channel. The emulator comprises transmit modules, receive modules and communication media modules, and can accept or output analog or digital signals. Each module is configurable to allow modeling of simplex or duplex communication, or a common base station with multiple users transmitting or receiving, all configurations with or without communication media impairment emulation. Each module can be configured to add a plurality of linear and non-linear impairments to a baseband signal.

Communication transmission impairment emulator

A method and system for rapidly acquiring a spreading code, used in a code division multiple access (CDMA) system. A first long code and a second long code, with each long code having a length of N chips, are generated. The first long code is different from the second long code. The first long code and the second long code are transmitted at a first phase angle and at a second phase angle, respectively, on a carrier signal, over a communications channel using radio waves. The first long code and the second long code may be transmitted at an in-phase (I) angle and at a quadrature-phase (Q) angle, respectively, on the carrier signal. From the communications channel, an I-phase acquisition circuit and a Q-phase acquisition circuit may acquire, in parallel, the first long code and the second long code from the I-phase angle and the Q-phase angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, the first long code and the second long code.

Rapid acquisition spreading codes for spread-spectrum communications

A spread spectrum system having an assignor, a spread-spectrum processor and a transmitter. The assignor assigns each arriving information signal to a message-code signal. Each message-code signal is different then other message-code signals. The spread-spectrum processor generates a pilot code signal and processes the information signals with the message-code signals to generate spread-spectrum process-message signals synchronized to the pilot-code signal. A transmitter combines the spread-spectrum process-message signals and the pilot-code signal to generate a CDM signal. The transmitter modulates the CDM signal with a carrier signal for transmission over the communications channel.

Spread spectrum system assigning information signals to message-code signals

Method and apparatus for an arbitrated high speed control data bus system providing high speed communications between microprocessor modules in a complex digital processing environment. The system features a simplified hardware architecture featuring fast FIFO queuing, TTL CMOS compatible level clocking signals, single bus master arbitration, synchronous clocking, DMA, and unique module addressing for multiprocessor systems. The system includes a parallel data bus with sharing bus masters residing on each processing module decreeing the communication and data transfer protocol. Bur arbitration is performed over a dedicated, independent, serial arbitration line. Each requesting module competes for access to the parallel data bus by placing the address of the requesting module on the arbitration line and monitoring the arbitration line for collisions, eliminating the need for both bus request and bus grant signals.

System and method for arbitration of a plurality of processing modules

A spread-spectrum system having an assignor, a spread-spectrum processor, a call processor, and an information-channel-mode modifier. The assignor assigns each information signal arriving at the spread-spectrum system to a message-code signal. Each of the message-code signals supports a pre-determined information-channel rate. Several information signals have different channel rates, and each information signal is assigned according to the required channel rate. The spread-spectrum processor generates a pilot-code signal, and spread-spectrum processes the information signals with the message-code signals to generate a plurality of spread-spectrum processed-message signals, respectively. The message-code signals are synchronized to the pilot-code signal. The call processor provides a call-type signal corresponding to the information signal rate for the several information signals having several different channel rates. In response to the call-type signal, the information-channel-mode modifier changes a combination of the information signals and the message-code signals to support the several different channel rates for the several information signals having several different channel rates.

Spread-spectrum system for assigning information signals having different data rates

An efficient, multichannel filter for CDMA modems permits multiple serial, digital bit streams to be filtered by digital signal processing techniques including sample weighting and summing functions. Each individual channel may have custom weighting coefficients or weighting coefficients common for all channels. If the weighting coefficients are by adapation, the same approach may be taken. The multichannel FIR filter is implemented with no multipliers and a reduction in the number of adders. To increase the speed of operation, the filter structure utilizes look-up tables storing the weighting coefficients. The invention can be embodied as either as a field programmable gate array or an application specific integrated circuit. The use of look-up tables saves significant chip resources.

An arbitration system which allows communication between a plurality of competing processing modules over a shared communication bus. The system comprises an arbitration line coupled to a controller located on each processing module. When a processing module desires access to the communication bus, each controller, executing the same arbitration protocol, shifts its respective module address onto the arbitration line and monitors the arbitration line to detect for collisions.

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.

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

Capacity management method for a code division multiple access (CDM) communication system

Code division multiple access (CDMA) communication system

A parallel packetized intermodule arbitrated high speed control data bus system which allows high speed communications between microprocessor modules in a more complex digital processing environment. The system features a simplified hardware architecture featuring fast FIFO queuing operating at 12.5 MHz, TTL CMOS compatible level clocking signals, single bus master arbitration, synchronous clocking, DMA, and unique module addressing for multiprocessor systems. The system includes a parallel data bus with sharing bus masters residing on each processing module decreeing the communication and data transfer protocols. Bus arbitration is performed over a dedicated serial arbitration line and each requesting module competes for access to the parallel data bus by placing the address of the requesting module on the arbitration line and monitoring the arbitration line for collisions.

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Huntington, NY, United States of America

Robert T Regis