Systems and method for orthogonal frequency divisional multiplexing
First Claim
1. A remote communication device for operation in a bidirectional communication system, the device comprising:
- at least one symbol mapper for mapping symbols using quadrature amplitude modulation (QAM) symbol mapping and phase-shift keying (PSK) symbol mapping;
an Inverse Fast Fourier Transform (IFFT) engine operating on frequency domain that receives a frame of parallel frequency domain data based on symbol data generated by the symbol mapper, the Inverse Fast Fourier Transform (IFFT) engine generating a frame of time domain in-phase and quadrature phase data from the frame of parallel frequency domain data which is generated based on symbol data generated by the symbol mapper;
at least one converter generating an analog signal based on the stream of time domain in-phase and quadrature phase data;
a radio frequency transmitter for transmitting a radio frequency signal based on the analog signal; and
a processor, wherein the symbol mapper is responsive to the processor, and the processor controls synchronization of symbol timing and carrier frequency of transmissions from the radio frequency transmitter.
0 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to de-modulate symbols from at least one of a plurality of spectrally overlapping carrier signals to produce a receiver output; a transmitter configured to modulate symbols onto at least one of a plurality of the spectrally overlapping carrier signals; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform to the data transmitted by the transmitter; the processor coupled to the receiver, wherein the processor applies a Fourier transform to the receiver output; and a controller programmed to instruct the transmitter to transmit at least one symbol representing a request for bandwidth allocation on a first carrier; wherein the controller is further programmed to determine when a collision has occurred on the first carrier.
24 Citations
12 Claims
-
1. A remote communication device for operation in a bidirectional communication system, the device comprising:
-
at least one symbol mapper for mapping symbols using quadrature amplitude modulation (QAM) symbol mapping and phase-shift keying (PSK) symbol mapping; an Inverse Fast Fourier Transform (IFFT) engine operating on frequency domain that receives a frame of parallel frequency domain data based on symbol data generated by the symbol mapper, the Inverse Fast Fourier Transform (IFFT) engine generating a frame of time domain in-phase and quadrature phase data from the frame of parallel frequency domain data which is generated based on symbol data generated by the symbol mapper; at least one converter generating an analog signal based on the stream of time domain in-phase and quadrature phase data; a radio frequency transmitter for transmitting a radio frequency signal based on the analog signal; and a processor, wherein the symbol mapper is responsive to the processor, and the processor controls synchronization of symbol timing and carrier frequency of transmissions from the radio frequency transmitter. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A remote communication device for a bi-directional communication system, the device comprising:
-
a modem that includes;
a symbol mapper that produces at least one stream of symbols;an Inverse Fast Fourier Transform (IFFT) engine operating on frequency domain that receives a frame of parallel frequency domain data which is generated based on symbol data generated by the symbol mapper, the Inverse Fast Fourier Transform (IFFT) engine generating a frame of time domain in-phase and quadrature phase samples from the symbol data generated by the symbol mapper; at least one converter receiving the time domain in-phase and quadrature phase samples and generating an analog signal based on the time domain samples; and an amplifier that amplifies for transmission a radio frequency carrier carrying the at least one analog signal; and
a processor that synchronizes the transmissions from the amplifier for combining with other signals. - View Dependent Claims (7, 8)
-
-
9. A remote communication device, the device comprising:
-
a symbol mapper that produces at least one stream of symbols; an Inverse Fast Fourier Transform (IFFT) engine operating on frequency domain that receives a frame of parallel frequency domain data which is generated based on symbol data generated by the symbol mapper, the Fast Fourier Transform (FFT) engine generating a frame of time domain in-phase and quadrature phase samples from the symbol data generated by the symbol mapper; at least one converter receiving the time domain in-phase and quadrature phase samples and generating an analog signal based on the time domain samples; and an amplifier that amplifies for transmission a radio frequency carrier carrying the at least one analog signal; a processor that causes transmissions from the amplifier to be orthogonal when received at a multipoint-to-point host unit. - View Dependent Claims (10, 11, 12)
-
Specification