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US 7,496,113 B2Granted
Fast cell search and accurate synchronization in wireless communications
AssigneeZTE (USA) Inc.
InventorsSean Cai, Wenzhong Zhang, Jing Wang, Jason Hou, Yonggang Fang, Yunsong Yang
Life of this patent
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Abstract
Techniques for fast cell search, selection and reselection for wireless communication systems such as OFDM or OFDMA communication systems. In various implementations of the described techniques, downlink subframes from base stations to mobile stations are designed to include information in form of preambles or post-ambles in one or more downlink subframes to facilitate cell search at receiving mobile stations at high speeds. The described preambles and post-ambles may also be used to improve the accuracy of signal synchronization in time and frequency.
Claims54
A method for wireless communications, comprising:
- using a cell identification sequence as a leading symbol of and as at least part of a preamble of every downlink subframe in time of a downlink signal from a base station to a mobile station, wherein the cell identification sequence is one of a set of cell identification sequences and is designated to identify a base station and a cell sector of the base station;
- including at least one data symbol, at a position subsequent to the cell identification sequence in time, in every downlink subframe of the downlink signal;
- and
- including in every other L frames of the downlink signal, at a position subsequent to the cell identification sequence in time, a symbol comprising a plurality of copies of a sequence placed sequentially in time,
- wherein L is an integer greater than 0 and the sequence is common to at least a portion of base stations with which the mobile station is communicating.
2 more elements
A method for wireless communications, comprising:
- controlling a mobile station to detect a downlink signal received from a base station, wherein the downlink signal comprises a cell identification sequence as a leading symbol of and as at least part of a preamble of every downlink subframe in time, at least one data symbol, at a position subsequent to the cell identification sequence in time, in every downlink subframe of the downlink signal, and, in every other L frames of the downlink signal, at a position subsequent to the cell identification sequence in time, a symbol comprising a plurality of copies of a sequence placed sequentially in time, wherein L is an integer greater than 0 and the sequence is common to at least a portion of base stations with which the mobile station is communicating,
- wherein the cell identification sequence is one of a set of cell identification sequences and is designated to identify a base station and a cell sector of the base station;
- controlling the mobile station to perform synchronization in time and frequency based on the sequence;
- and controlling the mobile station to perform a correlation between the cell identification sequencer and the set of cell identification sequences to identify the cell sector and the base station.
1 more element
A method for wireless communications, comprising:
- using one group identification sequence as part of a downlink subframe from a base station to a mobile station to identify a group of base stations, wherein different group identification sequences are respectively assigned to different groups of base stations and different base stations in one group have a common group identification sequence;
- including in the downlink subframe a cell identification sequence to identify a specific base station and a cell sector of the base station in the group identified by the one group identification sequence in the downlink subframe, wherein the cell identification sequence is one of a set of cell identification sequences and is designated to identify a base station and a cell sector of the base station;
- and
- including at least one data symbol, at a position subsequent to the cell identification sequence in time, in every downlink subframe of the downlink signal;
- and including in every other L frames of the downlink signal, at a position subsequent to the cell identification sequence in time, a symbol comprising a plurality of conies of a sequence placed sequentially in time, wherein L is an integer greater than 0 and the sequence is common to at least a portion of base stations with which the mobile station is communicating.
2 more elements
Dependencies are inferred from the claim text.