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US 7,031,753 B2Granted
Dynamic sub-carrier assignment in OFDM systems
AssigneeNortel Networks Limited
InventorsBassam M. Hashem, David G. Steer, Shalini S. Periyalwar
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AssigneeNortel Networks Limited
InventorsBassam M. Hashem, David G. Steer, Shalini S. Periyalwar
Estimating the term…
A method and apparatus are provided for selecting and signalling the identity of sub-carriers to be used for transmission of data in a radio communication system, and for using other sub-carriers. A remote unit determines which sub-carriers are acceptable for use in data transmission by comparing the signal to interference ratio of each sub-carrier with a threshold. A sequence of numbers is generated using one set of values to identify acceptable sub-carriers and another set of values to identify unacceptable sub-carriers. The sequence of numbers is transmitted to a base station. The average signal to interference ratio of sub-carriers whose signal to interference ratio was above the threshold can also be transmitted to the base station, thereby allowing the base station to determine an optimum set of transmission parameters for use only in the acceptable sub-carriers. Alternatively, the remote unit can determine the optimum set of transmission parameters itself for transmission to the base station. As yet another alternative, the remote unit can determine an optimum Link Mode for each acceptable sub-carrier, and use a reference to the Link Modes as the set of values identifying acceptable sub-carriers. The base station transmits data over the acceptable sub-carriers at the optimum Link Mode or Link Modes. The base station may use some of the unacceptable sub-carriers for transmission of low sensitivity data at the optimum Link Mode, and may use some of the unacceptable sub-carriers for transmission of data at a lower Link Mode. The transmission power of any unused unacceptable sub-carriers can be diverted to other sub-carriers.
A method by a base station in a radio communication system which employs Orthogonal Frequency Division Multiplexing, the radio communication system employing a plurality of sub-carriers, each sub-carrier belonging to one of a plurality of groups of sub-carriers, the base station receiving a return signal, the method comprising the steps of:
A base station for a radio communication system which employs a plurality of sub-carriers so as to employ Orthogonal Frequency Division Multiplexing, each sub-carrier belonging to one of a plurality of groups of sub-carrier, the base station receiving a return signal from a remote unit, the base station comprising:
A base station for a radio communication system which employs a plurality of sub-carriers, each sub-carrier belonging to one of a plurality of groups of sub-carriers, the base station receiving a return signal from a remote unit, the base station comprising:
A processor in a base station for a radio communication system which employs a plurality of sub-carriers so as to employ Orthogonal Frequency Division Multiplexing, each sub-carrier belonging to one of a plurality of groups of sub-carriers, the base station receiving a return signal from a remote unit, the processor including instructions for:
Dependencies are inferred from the claim text.