System and method for cyclic carrier de-rotation for earliest time of arrival estimation in a wireless communications system

A logic arrangement for estimating an earliest time of arrival of a received signal in a wireless communication system, which, when executed by a processing arrangement, is operable to perform the steps of:

• forming a complex vector having a first phase reference by combining one or more in-phase components and one or more quadrature components of a signal received on a wireless communication channel;
• computing a first time of arrival estimate of the received signal;
• computing a derivative complex vector, having a phase reference different from said first phase reference, from said complex vector;
• and
• computing at least a second time of arrival estimate of the received signal using derivative complex vector;
• wherein the earliest time of arrival of the received signal is the earliest of the time of arrival estimates.

A system for estimating an earliest time of arrival of a received signal in a wireless communication system, comprising:

• a processing arrangement operable to execute the following instructions:
• form a complex vector having a first phase reference by combining one or more in-phase components and one or more quadrature components of a signal received on a wireless communication channel,
• compute a first time of arrival estimate of the received signal,
• compute a derivative complex vector, having a phase reference different from said first phase reference, from said complex vector, and
• compute at least a second time of arrival estimate of the received signal using derivative complex vector;
• wherein the earliest time of arrival of the received signal is the earliest of the time of arrival estimates.

A system for estimating an earliest time of arrival of a received signal in a wireless communication system, comprising:

• a wireless receiver for receiving a signal;
• at least one A/D converter for converting the received signal into representative digital samples;
• at least one combining apparatus configurable to combine one or more in-phase and quadrature components of the received signal into a complex vector;
• at least one phase-shifting apparatus configurable to rotate the phase of the complex vector;
• at least one apparatus for determining at least one estimate of a time of arrival of the received signal based on at least one phase-shifted complex vector;
• and
• at least one comparing apparatus for comparing the at least one estimated time of arrival of the received signal;
• wherein the earliest time of arrival of the received signal is the earliest estimated time of arrival.

A wireless access point system for use in a wireless communication system, comprising:

• a wireless receiver for receiving a signal;
• at least one A/D converter for converting the received signal into representative digital samples;
• at least one combining apparatus configurable to combine one or more in-phase and quadrature components of the received signal into a complex vector;
• at least one phase-shifting apparatus configurable to rotate the phase of the complex vector;
• at least one apparatus for determining at least one estimate of a time of arrival of the received signal based on at least one phase-shifted complex vector;
• and
• at least one comparing apparatus for comparing the at least one estimated time of arrival of the received signal;
• wherein the earliest time of arrival of the received signal is the earliest estimated time of arrival.