Method and apparatus for code division switching

• US 6,954,440 B2
• Filed: 12/20/2000
• Issued: 10/11/2005
• Est. Priority Date: 12/20/2000
• Status: Expired due to Fees

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Gerakoulis, Diakoumis Parissis
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): BLOUNT, STEVEN
• Application Number:
  US09/741,540
• Publication Number:
  US 20020075821A1
• Time in Patent Office: 1,756 Days
• Field of Search: 370/320, 370/316, 370/323, 370/441, 370/442, 370/466, 370/342, 370/335, 370/325, 370/321, 370/322, 370/324, 370/336, 370/369, 370/370, 370/371, 370/372
• US Class Current: 370/320
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes

Abstract

Time division multiplexed input signals (i.e., separated into time slots) are spread in each time slot with a destination code. This spreading is applied for destination identification as opposed to signal information modulation. Each spreading signal is associated with a particular destination for a particular time slot. These spread signals are then combined on a code division bus. Output signals for retransmission to the destinations are recovered from the bus by application of despreading codes. Each despread signal has a destination code which appears in its individual time slot. In a variant code division multiplexed signals are directed to a destination by use of time slot interchanger to achieve time division switching to route the CDMA multiplexed channels.

Claims

1. A method of switching a signal comprising:

coupling an input to output by plural stages of switching;

processing the signal switching by coding techniques in one stage of the plural stages of switching;

processing the signal switching by timing techniques in another stage of the plural stage of switching;

coordinating the coding techniques and timing techniques to couple a signal at an input port to a predetermined output port;

despreading a code division signal;

time multiplexing the despread code division signal; and

respreading the time multiplexed signal.

2. A method of switching a signal comprising:

coupling an input to output by plural stages of switching;

processing the signal switching by coding techniques in one stage of the plural stages of switching;

processing the signal switching by timing techniques in another stage of the plural stages of switching;

coordinating the coding techniques and timing techniques to couple a signal at an input port to a predetermined output port;

spread coding a time multiplexed signal;

code division switching the spread coded signal; and

time multiplexing the code division switched signal.

3. A method of switching a signal comprising:

coupling an input to output by plural stages of switching;

processing the signal switching by coding techniques in one stage of the plural stages of switching, wherein the processing in one stage comprises;

switching by timing techniques comprises a time slot interchange step; and

switching by coding techniques comprises a code division step;

processing the signal switching by timing techniques in another stage of the plural stages of switching;

coordinating the coding techniques and timing techniques to couple a signal at an input port to a predetermined output port;

combining signals into beams and encoding the beams with overspreading techniques to identify a destination; and

coding individual signals to identify a particular user.