Synchronizing method for impulse radio network

• US 7,613,257 B2
• Filed: 10/28/2005
• Issued: 11/03/2009
• Est. Priority Date: 10/29/2004
• Status: Expired due to Fees

• Current Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Original Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Inventors: El Fawal, Alaeddine, Le Boudec, Jean-Yves
• Primary Examiner(s): Pathak; Sudhanshu C
• Application Number:
  US11/260,390
• Publication Number:
  US 20060093077A1
• Time in Patent Office: 1,467 Days
• Field of Search: 375/152, 375/150, 375/148, 375/149, 375/346, 375/260, 375/354, 375/343, 455/456.5
• US Class Current: 375/343
• CPC Class Codes: H04B 1/7183 Synchronisation

Abstract

A method to synchronize impulse radio signal in a receiver based on a cross-correlation between an input signal and a template pulse train is described. The method comprises the steps of receiving a radio signal, performing a correlation between the acquired radio signal and a template pulse train, splitting the correlation into at least two elementary correlations over intervals of predefined length and separated by a predetermined time to obtain elementary correlation output, performing an elementary threshold check on each elementary correlation output, summing the elementary threshold check outputs to form a sum result.

Claims

1. A method to synchronize an impulse radio signal in a receiver based on a cross-correlation between an input signal and a template pulse train, this method comprising:

a. receiving a radio signal,

b. applying a reference pulse train,

c. splitting the radio signal according to the template pulse train contained in the reference pulse train to obtain a plurality of elementary samples,

d. executing at least one unitary cross-correlation on at least one of the plurality of elementary samples with the reference pulse train to obtain a cross-correlation result,

e. applying a threshold check on each cross-correlation result, wherein each cross-correlation result has the same weighting to obtain a threshold-checked cross-correlation result,

f. summing each threshold-checked cross-correlation result to form a sum result of an output signal,

g. storing the sum result,

h. shifting the template pulse train by a predetermined offset,

i. performing steps b-to-g with the shifted template pulse train to the received radio signal,

j. determining the highest sum result over a given time period,

wherein the threshold-checked cross-correlation result has three states, i.e. positive, zero and negative.

2. Method of claim 1, wherein the threshold of the threshold check is set according to the minimum accepted signal to noise ratio.

3. Method of claim 1, wherein a main threshold check is performed on the sum result, and in case the sum result passes the main threshold check, the receiver locks on the impulse radio signal, otherwise the receiver shifts the template pulse train by a predefined offset and repeat b to f.

4. Method of claim 1, wherein the method further comprises:

locking the impulse radio signal at the phase corresponding to the highest sum result.

5. Method of claim 1, wherein the method further comprises:

comparing the highest sum result with a predefined threshold,

locking the impulse radio signal at the phase corresponding to the highest sum result if the highest sum result is above the threshold.