Method and apparatus using cell-specific and common pilot subcarriers in multi-carrier, multi-cell wireless communication networks
First Claim
1. In a multi-cell, Orthogonal Frequency Division Multiple Access (OFDMA) wireless communication system comprising a plurality of base stations in a plurality of cells, a transmission method comprising:
- arranging multiple adjacent cells in the system into a group with an associated group identifier;
synchronizing base stations in the group of adjacent cells in time and frequency to a common reference source;
forming a common set of pilot subcarriers by each base station in the group of adjacent cells;
selecting frequency-domain signal randomization to be applied on the common set of pilot subcarriers, wherein the frequency-domain signal randomization is specific to the group of adjacent cells and different from frequency-domain signal randomization applied on pilot subcarriers by a base station outside of the group of adjacent cells;
applying the group-specific frequency-domain signal randomization on the common set of pilot subcarriers in each base station in the group of adjacent cells; and
transmitting the common set of pilot subcarriers by the base stations in the group of adjacent cells using the same frequency subcarrier indices and the same time indices.
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Accused Products
Abstract
A multi-carrier cellular wireless network (400) employs base stations (404) that transmit two different groups of pilot subcarriers: (1) cell-specific pilot subcarriers, which are used by a receiver to extract information unique to each individual cell (402), and (2) common pilots subcarriers, which are designed to possess a set of characteristics common to all the base stations (404) of the system. The design criteria and transmission formats of the cell-specific and common pilot subcarriers are specified to enable a receiver to perform different system functions. The methods and processes can be extended to other systems, such as those with multiple antennas in an individual sector and those where some subcarriers bear common network/system information.
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Citations
16 Claims
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1. In a multi-cell, Orthogonal Frequency Division Multiple Access (OFDMA) wireless communication system comprising a plurality of base stations in a plurality of cells, a transmission method comprising:
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arranging multiple adjacent cells in the system into a group with an associated group identifier; synchronizing base stations in the group of adjacent cells in time and frequency to a common reference source; forming a common set of pilot subcarriers by each base station in the group of adjacent cells; selecting frequency-domain signal randomization to be applied on the common set of pilot subcarriers, wherein the frequency-domain signal randomization is specific to the group of adjacent cells and different from frequency-domain signal randomization applied on pilot subcarriers by a base station outside of the group of adjacent cells; applying the group-specific frequency-domain signal randomization on the common set of pilot subcarriers in each base station in the group of adjacent cells; and transmitting the common set of pilot subcarriers by the base stations in the group of adjacent cells using the same frequency subcarrier indices and the same time indices. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A multi-cell, Orthogonal Frequency Division Multiple Access (OFDMA) wireless communication system comprising a plurality of base stations in a plurality of cells, the system comprising:
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an apparatus configured to identify a group of adjacent cells in the system, the group of adjacent cells having an associated group identifier; an apparatus configured to synchronize base stations in the group of adjacent cells in time and frequency to a common reference source; an apparatus configured to form a common set of pilot subcarriers in each base station in the group of adjacent cells; an apparatus configured to perform frequency-domain signal randomization on the common set of pilot subcarriers in each base station in the group of adjacent cells, wherein the frequency-domain signal randomization is specific to the group of cells and different from frequency-domain signal randomization applied on pilot subcarriers by a base station outside of the group of adjacent cells; and an apparatus configured to transmit the common set of pilot subcarriers in the base stations in the group of adjacent cells using the same frequency subcarrier indices and the same time indices. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification