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Code Division Multiple Access Communication System Using Overlapping Spread Sequences

Summary

This Invention Discloses A Code Division Multiple Access Communications System Based On Spread Sequences Designed By Using Complete Factorization Of Polyphase Matrix Of A Perfect Reconstruction (Pr) Filter Bank. The Key Characteristic Is That The Length Of The Spread Sequence Is Longer Than The Period Of The Data Symbol I.E., The Data Symbols Are Spreaded By The Spread Sequence And Overlapped With Neighboring Data Symbols. The Design Method Includes An Orthogonal Code Generator, A Number Of Cascading Stages And Random Permutation Matrices. The Number Of Cascading Stages And Random Permutation Matrices Are Selected According To The Length Of The Spread Sequence Required. The Length Of The Spread Sequence Could Be Selected According To The System Performance Requirement, Hence The Overlapping Factor Of Spreaded Data Symbols. Furthermore, This Spread Sequence Assumes Integer Values Instead Of Binary When The Orthogonal Code Generator Generates A Walsh-Hadamard Code. The Number Of Integer Values Level Could Be Limited By Employing Proper Permutation Matrices. This Spread Sequence Generation Method Could Be Implemented Using Simple Integer Arithmetic. Furthermore, This Spread Sequences Are Highly Secured Since Random Permutation Matrices Are Used.

Supplementary Information

Patent Number: US6728295B1
Application Number: US2000607749A
Inventor: Nallanathan, Arumugam | Ng, Tung Sang | Chow, Shing
Priority Date: 30 Jun 1999
Priority Number: US6728295B1
Application Date: 30 Jun 2000
Publication Date: 27 Apr 2004
IPC Current: H04J001100
US Class: 375140 | 370208
Assignee Applicant: The University of Hong Kong
Title: Code division multiple access communication system using overlapping spread sequences
Usefulness: Code division multiple access communication system using overlapping spread sequences
Summary: Code division multiple access (CDMA) communication system including personal communication system (PCS) and digital cellular system.
Novelty: Code division multiple access communication system has random permutation matrices which are used at every cascading stages to randomize spread sequences based on which data symbols are spread

Industry

ICT/Telecom

Sub Category

Telecommunication

Application No.

US2000607749A

Country/Region

Hong Kong