System and method for robust ofdm synchronization
AssigneeHughes Network Systems, LLC
InventorsDonglei Fan, Bassel Beidas
Life of this patent
Estimating the term…
Abstract
Systems and methods are disclosed and include a method that includes adding a training symbol prefix to an OFDM symbol frame, the prefix including a plurality of training symbols, each including N sub-symbol fields. N/2 of the sub-symbol fields are zero valued, and N/2 of the sub-symbol fields carry corresponding symbols of a N/2 sub-symbol pseudo random training symbol. A first half of the pseudo random training symbol is symmetrical to a second half of the pseudo random training symbol. An OFDM N-sub-carrier transmission carries the prefix as signal power on a first N/2 of its N sub-carriers and suppresses signal power on a second N/2 of the sub-carriers. The first N/2 and second N/2 sub-carriers alternate in the frequency domain.
Claims20
A system for synchronizing a receiving of an orthogonal frequency division multiplexing (OFDM), the system comprising:
- an input data interface configured to receive a sequence of signal samples and associated indexes;
- a processing unit;
- and
- a memory configured to a store a plurality of instructions that when read and executed by the processing unit cause the processing unit to:
- generate an OFDM symbol frame,
- add a training symbol prefix to the OFDM symbol frame, the training symbol prefix including a plurality of training symbols, each of the training symbols including N sub-symbol fields, wherein
- a first N/2 of the sub-symbol fields are set at a zero value,
- a second N/2 of the sub-symbol fields carry corresponding symbols of a N/2 sub-symbol pseudo random training symbol, and
- a first half of the N/2 sub-symbol pseudo random training symbol is symmetrical to a second half of the N/2 sub-symbol pseudo random training symbol, and
- transmit the training symbol prefix as a multi-carrier transmission within an OFDM N-sub-carrier transmission, the transmit being configured such that:
- the multi-carrier prefix transmission carries signal power on a first N/2 of the N sub-carriers and suppresses signal power on a second N/2 of the sub-carriers, and
- the first N/2 sun-carriers and the second N/2 sub-carriers are respectively aligned at alternating positions in the frequency domain.
A method for communicating a robust synchronization orthogonal frequency division multiplexing (OFDM) frame, comprising:
- generating an OFDM symbol frame;
- adding a training symbol prefix to the OFDM symbol frame, the training symbol prefix including a plurality of training symbols, each of the training symbols including N sub-symbol fields, wherein
- a first N/2 of the sub-symbol fields are set at a zero value,
- a second of the N/2 sub-symbol fields carry corresponding symbols of a N/2 sub-symbol pseudo random training symbol, and
- a first half of the pseudo random training symbol is symmetrical to a second half of the pseudo random training symbol;
- and
- transmitting the training symbol prefix as a multi-carrier transmission within an OFDM N-sub-carrier transmission, wherein
- the multi-carrier prefix transmission carries signal power on a first N/2 of the N sub-carriers and suppresses signal power on a second N/2 of the sub-carriers, and
- the first N/2 sub-carriers and the second N/2 sub-carriers are respectively aligned at alternating positions in the frequency domain.
A system for synchronizing a receiving of an orthogonal frequency division multiplexing (OFDM), the system comprising:
- an OFDM transmitter, configured to transmit a succession of OFDM information frames, each of the OFDM information frames carrying, on N sub-carriers, a block of OFDM symbols;
- and
- a training symbol insertion unit configured to insert training symbol prefixes between successive OFDM information frames, each training symbol prefix including a plurality of training symbols, each of the training symbols including N sub-symbol fields, the training symbol insertion unit being further configured to
- set a first N/2 of the sub-symbol fields to a zero value,
- form a second N/2 of the sub-symbol fields to carry corresponding symbols of a N/2 sub-symbol pseudo random training symbol, and
- form a first half of the N/2 sub-symbol pseudo random training symbol to be symmetrical to a second half of the N/2 sub-symbol pseudo random training symbol,
- wherein the OFDM transmitter is further configured to:
- transmit the training symbol prefix as a multi-carrier transmission within an OFDM N-sub-carrier transmission, wherein:
- the multi-carrier prefix transmission carries signal power on a first N/2 of the N sub-carriers and suppresses signal power on a second N/2 of the sub-carriers, and
- the first N/2 sun-carriers and the second N/2 sub-carriers are respectively aligned at alternating positions in the frequency domain.
Dependencies are inferred from the claim text.