SYSTEM ACCESS AND SYNCHRONIZATION METHODS FOR MIMO OFDM COMMUNICATIONS SYSTEMS AND PHYSICAL LAYER PACKET AND PREAMBLE DESIGN
First Claim
1. A method in an orthogonal frequency division multiplexing (OFDM) receiver, comprising at least one receive antenna, to perform fine synchronization, the OFDM receiver configured to communicate with a transmitter comprising at least one transmit antenna, the method comprising:
- at each of the at least one receive antenna receiving OFDM symbols containing a respective received frequency domain training sequence for each of the at least one transmit antenna;
performing fine synchronization in the frequency domain by looking for maximum correlations between known frequency domain training sequences and the received frequency domain training sequences.
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Accused Products
Abstract
A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame.
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Citations
5 Claims
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1. A method in an orthogonal frequency division multiplexing (OFDM) receiver, comprising at least one receive antenna, to perform fine synchronization, the OFDM receiver configured to communicate with a transmitter comprising at least one transmit antenna, the method comprising:
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at each of the at least one receive antenna receiving OFDM symbols containing a respective received frequency domain training sequence for each of the at least one transmit antenna; performing fine synchronization in the frequency domain by looking for maximum correlations between known frequency domain training sequences and the received frequency domain training sequences.
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2. A method comprising:
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converting a frequency domain representation of a common sync sequence into a time domain representation; transmitting the time domain representation twice, preceded by a cyclic prefix of the time domain representation. - View Dependent Claims (3, 4)
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5. A method of performing synchronization at an orthogonal frequency division multiplexing (OFDM) receiver comprising:
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at each of at least one receive antenna, sampling a received OFDM signal to produce a respective set of time domain samples, the received signal comprising a received training sequence; performing synchronization based on correlations between the received training sequence and a local copy of the training sequence; wherein performing synchronization based on correlations between the received training sequence and a local copy of the training sequence is done in the frequency domain, wherein the received training sequence is a frequency domain training sequence located on selected sub-carriers of the received OFDM signal.
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Specification