Method for using rapid acquisition spreading codes for spread-spectrum communications

• US 20020051434A1
• Filed: 12/21/2000
• Published: 05/02/2002
• Est. Priority Date: 10/23/1997
• Status: Abandoned Application

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Lomp, Gary R., Ozluturk, Fatih M.
• Application Number:
  US09/742,578
• Publication Number:
  US 20020051434A1
• Time in Patent Office: Days
• US Class Current: 370/335
• 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 1/708 Parallel implementation
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects

Abstract

A multiple access, spread-spectrum communication system processes a plurality of information signals received by a radio carrier station over telecommunication lines for simultaneous transmission over a radio frequency channel as a code-division-multiplexed signal to a group of subscriber units. The radio carrier station 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 radio carrier station includes a plurality of 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 code division multiplexed signal. The RCS includes a system channel controller is coupled to receive a remote call. A radio frequency transmitter is connected to all of the modems to combine the code division multiplexed processed signals with the global pilot code signal to generate a code division multiplexed signal. The transmitter also modulates a carrier signal with the code division multiplexed signal and transmits the modulated carrier signal through a radio frequency communication channel to the subscriber units. Each subscriber unit includes a CDMA modem which is also synchronized to the global pilot signal. The CDMA modem despreads the code division multiplexed 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 radio carrier station and the subscriber units, and system capacity management for maintaining a maximum number of active subscriber units for improved system performance.

Claims

1. A multiple access, spread-spectrum communication system for processing a plurality of telecommunications information signals received simultaneously for simultaneous transmission over a radio frequency (RF) channel as a code-division-multiplexed (CDM) signal, the system comprising:

means for receiving a call request signal corresponding to a telecommunication line information signal, and a user identification signal identifying a user to which the call request and information signal are addressed;

a plurality of modem processing means, one of the plurality of modem processing means providing a global pilot code signal, and each of the modem processing means providing a respective message code signal and combining one of the plurality of information signals with the respective message code signal to provide a spread-spectrum processed message signal, the plurality of message code signals of the plurality of modem processing means being synchronized to the global pilot code signal;

assignment means responsive to a channel assignment signal for coupling the information signals received on the telecommunication lines to respective indicated ones of the plurality of modem means;

a system channel controller, coupled to a remote call-processing means and responsive to the user identification signal, for providing the channel assignment signal; and

an RF transmitter means, connected to each of the plurality of spread-spectrum processed message signals with the global pilot code signal to generate a CDM signal;

for modulating a carrier signal with the CDM signal and for transmitting the modulated carrier signal through an RF communication channel.