Physical layer structures and initial access schemes in an unsynchronized communication network
First Claim
1. A method of transmitting information in an unsynchronized Orthogonal Frequency Division Multiplexing (OFDM) communication network comprising a plurality of base stations, the method comprising:
- modulating access channel information onto a predetermined initial access channel of an OFDM communications signal, wherein the access channel information comprises a common synchronization code that is common to each of the plurality of base stations and a cell-specific synchronization code that is orthogonal to the common synchronization code and unique to each base station, and wherein the initial access channel comprises a predetermined set of one or more time-continuous signal components of the OFDM communications signal, each time-continuous signal component being carried by a respective sub-carrier;
and transmitting the communication signal.
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Accused Products
Abstract
Physical layer structures and related access schemes for unsynchronized communication networks are provided. Access channel information, preferably including a common synchronization code associated with all transceiver stations in a communication network and a cell-specific synchronization code uniquely associated with one of the transceiver stations, is modulated onto at least one set of time-continuous signal components of a communication signal. In order to access the communication network, communication terminals search for the access channel information in one or more sets of time-continuous signal components and synchronization parameters are then determined based on a location of the access channel information in the sets of time-continuous signal components. Some embodiments of the invention provide for joint frame synchronization and coarse timing synchronization. In further embodiments, the communication signal also includes a scattered pilot channel onto which a portion of the access channel information, preferably the cell-specific synchronization code, is modulated. The pilot channels may then be re-used for initial access operations in addition to its conventional uses for such operations as channel estimation.
110 Citations
15 Claims
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1. A method of transmitting information in an unsynchronized Orthogonal Frequency Division Multiplexing (OFDM) communication network comprising a plurality of base stations, the method comprising:
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modulating access channel information onto a predetermined initial access channel of an OFDM communications signal, wherein the access channel information comprises a common synchronization code that is common to each of the plurality of base stations and a cell-specific synchronization code that is orthogonal to the common synchronization code and unique to each base station, and wherein the initial access channel comprises a predetermined set of one or more time-continuous signal components of the OFDM communications signal, each time-continuous signal component being carried by a respective sub-carrier; and transmitting the communication signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of transmitting information in an unsynchronized Orthogonal Frequency Division Multiplexing (OFDM) communication network comprising a plurality of base transceiver stations, the method comprising:
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modulating a cell-specific synchronization code uniquely associated with a selected one of the plurality of base transceiver stations onto a scattered pilot channel of an OFDM communication signal; modulating access channel information to a predetermined initial access channel of the OFDM communications signal, wherein the access channel information comprises the cell-specific synchronization code and a common synchronization code that is orthogonal to the cell-specific synchronization code and common to each of the plurality of base transceiver stations, and wherein the initial access channel comprises a predetermined set of one or more time-continuous signal components of the OFDM communications signal, each time-continuous signal component being carried by a respective sub-carrier; and transmitting the communication signal. - View Dependent Claims (8, 9, 10, 11)
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12. A base transceiver station in an unsynchronized Orthogonal Frequency Division Multiplexing (OFDM) communication network comprising a plurality of base transceiver stations, the base transceiver station comprising:
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a. a processor configured to map access channel information to a predetermined initial access channel of an OFDM communications signal, wherein the access channel information comprises a common synchronization code that is common to all of the base transceiver stations in the network and a cell-specific synchronization code that is orthogonal to the common synchronization code and unique to the base transceiver station, and wherein the initial access channel comprises a predetermined set of one or more time-continuous signal components of the OFDM communications signal, each time-continuous signal component being carried by a respective sub-carrier; and b. an output configured to transmit the communication signal. - View Dependent Claims (13)
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14. A communication terminal comprising:
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an input configured to receive an OFDM communication signal; and a processor configured to search the received signal for predetermined access channel information in an initial access channel corresponding to a predetermined set of one or more time-continuous signal components of the OFDM communications signal, each time-continuous signal component being carried by a respective sub-carrier, and to determine synchronization parameters based on a location of the access channel information in the initial access channel; wherein the access channel information comprises a common synchronization code that is common to each of the plurality of base stations and a cell-specific synchronization code that is orthogonal to the common synchronization code and unique to each base station. - View Dependent Claims (15)
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Specification