Channel estimation sequence and method of estimating a transmission channel which uses such a channel estimation

A method of estimating a characteristic of a transmission channel between a transmitter and a receiver, comprising:

• transmitting from said transmitter to said receiver a channel estimation sequence (SE) comprising concatenated sequences S comprising sequence s and at least one of an extension esf comprising a copy of a rear portion of sequence s and an extension esd comprising a copy of a front portion of sequence s, and G comprising complementary sequence g and at least one of an extension egf comprising a copy of a rear portion of sequence g and an extension egd comprising a copy of a front portion of sequence g;
• receiving said channel estimation sequence (SE) at said receiver;
• correlating the received channel estimation sequence (SE) with sequence s so as to produce a first correlation result;
• delaying the complementary sequence g;
• correlating the delayed complementary sequence g with received channel estimation sequence (SE) so as to produce a second correlation result;
• and
• adding said first correlation result and said second correlation, wherein
• said delaying step comprises delaying the complementary sequence g by a delay equal to a length of sequence S.

A communication system, comprising:

• a transmitter configured to transmit a channel estimation sequence (SE) including concatenated sequences S having sequence s and at least one of an extension esf comprising a copy of a rear portion of sequence s and an extension esd comprising a copy of a front portion of sequence s, and G comprising complementary sequence g and at least one of an extension egf comprising a copy of a rear portion of sequence g and an extension egd comprising a copy of a front portion of sequence g;
• and
• a receiver configured to receive said channel estimation sequence (SE), said receiver comprising
• a first correlator configured to correlate the received channel estimation sequence (SE) with sequence s so as to produce a first correlation result,
• a delay module configured to delay the complementary sequence g,
• a second correlator configured to correlate the delayed complementary sequence g with the received channel estimation sequence (SE) so as to produce a second correlation result, and
• an adder configured to add said first correlation result and said second correlation, wherein
• said delay module is configured to delay said received channel estimation sequence (SE) by a delay equal to a length of sequence S.