Enhanced synchronization burst for OFDM systems
AssigneeCisco Technology, Inc.
InventorVincent K. Jones
Life of this patent
Estimating the term…
Abstract
A burst timing synchronization system useful in, e.g., OFDM communication systems. In one embodiment, this burst timing synchronization system may be impervious to the effects of dispersive channels and robust to noise and other interference. Special synchronization bursts may be used to both provide synchronization information and to carry data.
Claims16
A system for transmitting an OFDM signal via a channel to facilitate receiver synchronization comprising:
- a transforming stage that transforms a first series of N frequency domain symbols into a first burst of N time domain symbols and that transforms a second series of M frequency domain data symbols into a second burst of M time domain symbols;
- a cyclic prefix appending stage that appends to a beginning of said first time domain burst a first cyclic prefix duplicating a last segment of said first time domain burst to form a first synchronization burst, and that appends to a beginning of said second time domain burst a second cyclic prefix duplicating a last segment of said second time domain burst to form a second synchronization burst, said first and second cyclic prefixes including a first portion having length v wherein v is greater than or equal to a duration of an impulse response of said channel;
- and further including a second portion after said first portion to facilitate receiver synchronization;
- and
- wherein said first and second synchronization bursts are transmitted concatenated together.
A system for synchronizing to a time domain signal received via a channel, said system comprising:
- a receiver system that receives one or more synchronization bursts of symbols, each of said synchronization bursts including at least two time domain synchronization sub-bursts, a first of said sub-bursts including N time domain symbols preceded by a first cyclic prefix, a second of said sub-bursts including M time domain symbols preceded by a second cyclic prefix, said first and second cyclic prefixes including a first portion having length v wherein v is greater than or equal to a duration of an impulse response of said channel;
- and further including a second portion after said first portion to facilitate receiver synchronization, wherein said receiver system receives further time domain bursts of symbols;
- and
- a synchronization block that determines burst timing alignment responsive to optimization of a cost function determined responsive to said contents of said one or more synchronization bursts.
In a digital communication system that communicates bursts of symbols via a channel, a method for synchronizing a receiver to burst timing of a transmitter comprising:
- receiving one or more synchronization bursts of symbols, each said synchronization bursts including at least two time domain synchronization sub-bursts, a first of said sub-bursts including N time domain symbols preceded by a first cyclic prefix, a second of said sub-bursts including M time domain symbols preceded by a second cyclic prefix, said first and second cyclic prefixes including a first portion having length v wherein v is greater than or equal to a duration of an impulse response of said channel;
- and further including a second portion after said first portion to facilitate receiver synchronization, wherein said receiver receives further time domain bursts of symbols;
- and
- determining burst timing alignment responsive to optimization of a cost function
Dependencies are inferred from the claim text.