Channel probing signal for a broadband communication system
First Claim
1. A communication method for a mobile device served by a base station in a communication system employing Orthogonal Frequency Division Multiplexing (OFDM), the mobile device transmitting data information on data subcarriers and control information on control subcarriers in an uplink frequency band to the base station, the method comprising:
- receiving, at the mobile device, an instruction from the serving base station to transmit a probing signal;
forming, in response to the received instruction, the probing signal with a code sequence modulated in the frequency domain, wherein;
the probing signal is configured to overlap, in the time domain, with uplink signals transmitted over the uplink frequency band of the communication system; and
the probing signal is configured to overlap, in the frequency domain, with the data subcarriers but to avoid the control subcarriers in the uplink frequency band of the communication system; and
transmitting the probing signal to the serving base station.
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Accused Products
Abstract
In a broadband wireless communication system, a spread spectrum signal is intentionally overlapped with an OFDM signal, in a time domain, a frequency domain, or both. The OFDM signal, which inherently has a high spectral efficiency, is used for carrying broadband data or control information. The spread spectrum signal, which is designed to have a high spread gain for overcoming severe interference, is used for facilitating system functions such as initial random access, channel probing, or short messaging. Methods and techniques are devised to ensure that the mutual interference between the overlapped signals is minimized to have insignificant impact on either signal and that both signals are detectable with expected performance by a receiver.
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Citations
20 Claims
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1. A communication method for a mobile device served by a base station in a communication system employing Orthogonal Frequency Division Multiplexing (OFDM), the mobile device transmitting data information on data subcarriers and control information on control subcarriers in an uplink frequency band to the base station, the method comprising:
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receiving, at the mobile device, an instruction from the serving base station to transmit a probing signal; forming, in response to the received instruction, the probing signal with a code sequence modulated in the frequency domain, wherein; the probing signal is configured to overlap, in the time domain, with uplink signals transmitted over the uplink frequency band of the communication system; and the probing signal is configured to overlap, in the frequency domain, with the data subcarriers but to avoid the control subcarriers in the uplink frequency band of the communication system; and transmitting the probing signal to the serving base station. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A communication method for a base station serving a plurality of mobile devices in a communication system employing Orthogonal Frequency Division Multiplexing (OFDM), the base station receiving data information on data subcarriers and control information on control subcarriers in an uplink frequency band from the plurality of mobile devices, the method comprising:
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transmitting an instruction to one of the plurality of mobile devices to transmit a probing signal, wherein; the probing signal is formed with a code sequence modulated in the frequency domain; the probing signal is configured to overlap, in the time domain, with uplink signals transmitted over the uplink frequency band of the communication system; and the probing signal is configured to overlap, in the frequency domain, with the data subcarriers but to avoid the control subcarriers in the uplink frequency band of the communication system; and receiving the probing signal from the one of the plurality of the mobile devices. - View Dependent Claims (9, 10, 11, 12)
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13. A mobile device served by a base station in a communication system employing Orthogonal Frequency Division Multiplexing (OFDM), the mobile device transmitting data information on data subcarriers and control information on control subcarriers in an uplink frequency band to the base station, the mobile device comprising:
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a receiver configured to receive an instruction from the serving base station to transmit a probing signal; a processor configured to form, in response to the received instruction, the probing signal with a code sequence modulated in the frequency domain, wherein; the probing signal is configured to overlap, in the time domain, with uplink signals transmitted over the uplink frequency band of the communication system; and the probing signal is configured to overlap, in the frequency domain, with the data subcarriers but to avoid the control subcarriers in the uplink frequency band of the communication system; and a transmitter configured to transmit the probing signal to the serving base station. - View Dependent Claims (14, 15)
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16. A base station serving a plurality of mobile devices in a communication system employing Orthogonal Frequency Division Multiplexing (OFDM), the base station receiving data information on data subcarriers and control information on control subcarriers in an uplink frequency band from the plurality of mobile devices, the base station comprising:
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a transmitter configured to transmit an instruction to one of the plurality of mobile devices to transmit a probing signal, wherein; the probing signal is formed with a code sequence modulated in the frequency domain; the probing signal is configured to overlap, in the time domain, with uplink signals transmitted over the uplink frequency band of the communication system; and the probing signal is configured to overlap, in the frequency domain, with the data subcarriers but to avoid the control subcarriers in the uplink frequency band of the communication system; and a receiver configured to receive the probing signal from the one of the plurality of mobile devices. - View Dependent Claims (17, 18, 19)
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20. A communication system employing Orthogonal Frequency Division Multiplexing (OFDM), wherein data information is transmitted on data subcarriers and control information is transmitted on control subcarriers in an uplink frequency band, the communication system comprising:
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a base station configured to transmit an instruction requesting a probing signal; and a mobile device configured to; receive the instruction from the base station requesting a probing signal; form, in response to the received instruction, the probing signal with a code sequence modulated in the frequency domain, wherein; the probing signal is configured to overlap, in the time domain, with uplink signals transmitted over the uplink frequency band of the communication system; and the probing signal is configured to overlap, in the frequency domain, with the data subcarriers but to avoid the control subcarriers in the uplink frequency band of the communication system; and transmit the probing signal to the requesting base station.
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Specification