Sequence synchronization
First Claim
1. Apparatus for transmitting a data sequence from a transmitter to a receiver, including means at the transmitter for scrambling the data sequence by modulo addition thereto of a pseudo random sequence (PRS) output from a PRS generator at the transmitter, and means at the receiver for unscrambling the received scrambled data sequence by modulo subtraction therefrom of the same PRS, the PRS at the receiver being generated by a respective PRS generator threat, the receiver PRS generator being synchronised to the transmitter PRS generator by means of samples taken from the transmitter PRS and conveyed to synchronisation means at the receiver, and wherein the transmitter includes a PRS sample mapping block and the receiver includes a functionally complementary sample mapping block and the time of transmission of the conveyed samples is decoupled from the points in the PRS for which they were selected, the conveyed samples being skewed with respect to the PRS, and wherein the transmitter sample mapping block is such that a plurality of linearly independent samples are selected from the PRS, each sample being selected at a regular interval mutually prime with respect to the PRS cycle length.
8 Assignments
0 Petitions
Accused Products
Abstract
A data sequence is transmitted from a transmitter to a receiver, being scrambled at the transmitter by adding a pseudo random sequence (PRS) thereto. At the receiver the received data is unscrambled by subtraction of the same PRS. The receiver PRS generator is synchronised to the transmitter PRS generator by means of samples conveyed from the transmitter to the receiver. The transmitter includes a PRS sample mapping block, the receiver includes a functionally complementary sample mapping block and the time of transmission of the conveyed samples is decoupled from the points in the PRS for which they were selected, the conveyed samples being skewed with respect to the PRS.
-
Citations
14 Claims
- 1. Apparatus for transmitting a data sequence from a transmitter to a receiver, including means at the transmitter for scrambling the data sequence by modulo addition thereto of a pseudo random sequence (PRS) output from a PRS generator at the transmitter, and means at the receiver for unscrambling the received scrambled data sequence by modulo subtraction therefrom of the same PRS, the PRS at the receiver being generated by a respective PRS generator threat, the receiver PRS generator being synchronised to the transmitter PRS generator by means of samples taken from the transmitter PRS and conveyed to synchronisation means at the receiver, and wherein the transmitter includes a PRS sample mapping block and the receiver includes a functionally complementary sample mapping block and the time of transmission of the conveyed samples is decoupled from the points in the PRS for which they were selected, the conveyed samples being skewed with respect to the PRS, and wherein the transmitter sample mapping block is such that a plurality of linearly independent samples are selected from the PRS, each sample being selected at a regular interval mutually prime with respect to the PRS cycle length.
-
11. A method of transmitting a data sequence from a transmitter to a receiver including the steps of scrambling the data sequence by modulo addition thereto of a pseudo random sequence (PRS) output from a PRS generator at the transmitter, and unscrambling the received scrambled data sequence at the receiver by modulo subtraction therefrom of the same PRS, the PRS at the receiver being generated by a respective PRS generator thereat, the receiver PRS generator being synchronised to the transmitter PRS generator by taking samples from the transmitter PRS and conveying the samples to synchronisation means at the receiver, the samples taken being added with predetermined skew to the data sequence for transmission whereby the time of transmission of the conveyed samples is decoupled from the points in the PRS for which they were selected, and wherein a plurality of linearly independent samples are selected from the transmitter PRS, each sample being selected at a regular interval mutually prime with respect to the PRS cycle length.
- 12. A method as claimed in claim 12 wherein the plurality of samples are conveyed to the receiver at selected positions in the transmitted data sequence and wherein at the receiver their position is located and they are applied to receiver synchronisation means, said synchronisation means having knowledge of their original relative positions and absolute positions in respect of the scrambled data sequence.
Specification