Channel estimation by time multiplexed complementary sequences
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsMarian Rudolf, Bruno Jechoux
Life of this patent
Estimating the term…
Abstract
A method of estimating qualities of a transmission or telecommunications channel involves using a pair of complementary sequences s(n) and g(n), with n=0, 1, . . . , N−1, which have the property that the sum of their auto-correlations is a perfect Dirac function (that is, Φs,s(n)+Φg,g(n)=k·δ(n)). A composite signal made up of two complementary sequences s(n) and g(n) is used, after having time multiplexed these two sequences in such a way as to exploit the property Φs,s(n)=Φg,g(n)=k·δ(n). The composite signal is made up of two sequences which are concatenated with, between them, a guard interval of a duration greater than or equal to the length of the impulse response of the channel to be estimated.
Claims6
A method of estimating a transmission or telecommunications channel, comprising:
- using two complementary sequences s(n) and g(n), wherein n=0, 1, . . . , N−1, that have a property that a sum of their auto-correlations Φs,s(n)+Φg,g(n) is a Dirac function k·δ(n), where Φs,s(n) is the auto-correlation of s(n) and Φg,g(n) is the auto-correlation of g(n), k is an integer and δ(n) is a Dirac impulse;
- time multiplexing the two sequences;
- and
- forming a composite signal that includes the two complementary sequences and provides the estimation of the channel.
An apparatus for generating, at an apparatus output, a composite signal that includes two complementary sequences s(n) and g(n), wherein n=0, 1, . . . , N−1 , that have a property that a sum of their auto-correlations Φs,s(n)+Φg,g(n) is a Dirac function k·δ(n), where Φs,s(n) is the auto-correlation of s(n) and Φg,g(n) is the auto-correlation of g(n), k is an integer and δ(n) is a Dirac impulse, the apparatus comprising:
- a first circuit configured to generate s(n) at a first output;
- a second circuit configured to generate a guard interval sequence Npg=0 at a second output;
- a third circuit configured to generate g(n) at a third output;
- and
- a time multiplexing circuit configured to selectively connect the first, second and third outputs to the apparatus output to obtain an estimation of a communications channel.
An apparatus for providing an estimation of a transmission channel based on correlation of a received signal r(n) and a composite sequence e(n), the apparatus comprising:
- a receiver configured to receive the signal r(n);
- and
- a correlator configured to input the signal r(n) received in the receiver and establish a correlation between signal r(n) and signal e(n) according to the relation e(n)=s(n)+g(n−N−Npg) that includes a composite signal that includes two complementary sequences s(n) and g(n), wherein n=0, 1, . . . , N−1, that have a property that a sum of their auto-correlations Φs,s(n)+Φg,g(n) is a Dirac function k·δ(n)
- to provide the estimation of the channel, where Npg is a guard interval, Φs,s(n) is the auto-correlation of s(n) and Φg,g(n) is the auto-correlation of g(n), k is an integer, and δ(n) is a Dirac impulse.
An apparatus for providing an estimation h(n) of a transmission channel to which is applied a signal e(n)=s(n)+g(n−N−Npg) that includes a composite signal that includes two complementary sequences s(n) and g(n), wherein n=0, 1, . . . , N−1, that have a property that a sum of their auto-correlations Φs,s(n)+Φg,g(n) is a Dirac function k·Φ(n), where Npg is a guard interval, Φs,s(n) is the auto-correlation of s(n) and Φg,g(n) is the auto-correlation of g(n), k is an integer, and δ(n) is a Dirac impulse, the apparatus comprising:
- a) a first correlator configured to provide a first correlation output based on correlation of s(n) and a signal r(n) received in a receiver;
- b) a second correlator configured to provide a second correlation output based correlation of g(n) and r(n);
- c) a multiplexer including,
- 1) a first movable contact connected to the first correlation output and configured to be closed during a time interval N+Npg and open thereafter, and
- 2) a second movable contact connected to the second correlation output and configured to be open during the time interval N+Npg and closed thereafter;
- d) a first delay circuit, connected to the first contact, configured to provide a first delay d1 and to provide a first delay output;
- e) a second delay circuit, connected to the second contact, configured to provide a second delay d2 and to provide a second delay output, wherein a difference between delays d1 and d2 is equal to N+Npg;
- and
- f) an adder, configured to receive the first and second delay outputs and to provide the estimation h(n).
An apparatus for providing an estimation of a channel to which is applied a signal e(n)=s(n)+g(n−N−Npg) that includes a composite that includes two complementary sequences s(n) and g(n), wherein n=0, 1, . . . , N−1, that have a property that a sum of their auto-correlations Φs,sn)+Φg,g(n) is a Dirac function k·δ(n), where Npg is a guard interval, Φs,s(n) is the auto-correlation of s(n) and Φg,g(n) is the auto-correlation of g(n), k is an integer, and δ(n) is a Dirac impulse, the apparatus comprising:
- a) a Golay correlator having two inputs that receive in parallel a signal r(n) received in the receiver,
- b) a multiplexer including,
- 1) a first movable contact connected to the first correlation output and configured to be closed during a time interval N+Npg and open thereafter, and
- 2) a second movable contact connected to the second correlation output and configured to be open during the time interval N+Npg and closed thereafter;
- c) a first delay circuit, connected to the first contact, configured to provide a first delay d1 and to provide a first delay output;
- d) a second delay circuit, connected to the second contact, configured to provide a second delay d2 and to provide a second delay output, wherein a difference between delays d1 and d2 is equal to N+Npg;
- and
- e) an adder, configured to receive the first and second delay outputs and to provide the estimation h(n).
Dependencies are inferred from the claim text.