US 2004/0071239 A1 · Method and apparatus for compensating for the frequency offset in interleaved frequency division multiple access

Abstract

Provided are a method and apparatus for compensating for a frequency offset in an interleaved frequency division multiple access. The method compensates for a frequency offset between a transmission signal and a reception signal for a uth user (1≦u≦U, where U denotes the number of users) in an interleaved frequency division multiple access. The method includes: (a) estimating the frequency offset from a selection signal that is determined as the reception signal for the uth user in an initial mode and as a feedback signal in a normal mode; (b) estimating multiple access interferences representing an extent to which reception signals for ith other users (1≦i≦U−1) at the same time interfere with the reception signal for the uth user; (c) subtracting the estimated multiple access interferences from the reception signal for the uth user and determining the subtraction result as the feedback signal; (d) determining whether steps (a), (b), and (c) have been repeated a predetermined number of times, and if it is determined that steps (a), (b), and (c) have not been repeated the predetermined number of times, going back to step (a); and (e) if it is determined that steps (a), (b), and (c) have been repeated the predetermined number of times, estimating the transmission signal for the uth user using the feedback signal finally determined in step (c) and the estimated frequency offset.

Claims13

Dependent claims

A method of compensating for a frequency offset between a transmission signal and a reception signal for a uth user (1≦u≦U, where U denotes the number of users) in an interleaved frequency division multiple access system, the method comprising the steps of:

(a) estimating the frequency offset from a selection signal that is determined as the reception signal for the uth user in an initial mode and as a feedback signal in a normal mode;
(b) estimating multiple access interferences representing an extent to which reception signals for ith other users (1≦i≦U−1) at the same time interfere with the reception signal for the uth user;
(c) subtracting the estimated multiple access interferences from the reception signal for the uth user and determining the subtraction result as the feedback signal;
(d) determining whether steps (a), (b), and (c) have been repeated a predetermined number of times, and if it is determined that steps (a), (b), and (c) have not been repeated the predetermined number of times, going back to step (a);
and
(e) if it is determined that steps (a), (b), and (c) have been repeated the predetermined number of times, estimating the transmission signal for the uth user using the feedback signal finally determined in step (c) and the estimated frequency offset.

3 more elements

An apparatus for compensating for a frequency offset between a transmission signal and a reception signal for an uth user (1≦u≦U, where U denotes the number of users) in an interleaved frequency division multiple access, the apparatus comprising:

a main frequency offset estimator for determining the reception signal for the uth user or a feedback signal as a selection signal in response to a first control signal, estimating the frequency offset from the selection signal, and outputting the estimated frequency offset;
an extent estimator for estimating multiple access interferences representing an extent to which reception signals for from ith other users (1≦i≦U−1) interfere with the reception signal for the uth user, from the reception signals for the ith other users, the selection signal, and the estimated frequency offset, and outputing the estimated multiple access interferences;
a subtractor for subtracting the estimated interferences from the reception signal for the uth user and outputting the subtraction result as the feedback signal;
a controller for generating the first control signal in response to the result obtained by analyzing the state of the apparatus for compensating for the frequency offset, checking whether a predetermined period of time has elapsed, and outputting a second control signal in response to the checked result;
and
a transmission signal estimator for estimating the transmission signal for the uth user from the feedback signal finally input from the subtractor and the estimated frequency offset in response to the second control signal and outputting the estimated transmission signal,
wherein the main frequency offset estimator, the extent estimator, and the subtractor are enabled in response to the second control signal.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for compensating for the frequency offset in interleaved frequency division multiple access

Life of this patent

Method and apparatus for compensating for the frequency offset in interleaved frequency division multiple access

Life of this patent

Abstract

Claims13