Abstract:
Methods and apparatus for subframe configuration and generation in a multi-cell multi-carrier system. A frame for radio transmission in the system consists of multiple subframes, and each subframe consists of multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols. Training symbols, frequency-domain data scrambling, size of Fast-Fourier Transform (FFT), or length of cyclic prefix can be configured differently for each subframe to facilitate different applications, such as unicasting or broadcasting.
Abstract:
The present invention relates to demodulation of radio signals from a base station having collocated transmit antennas, and more particularly to signaling allocation information from a base station to a mobile terminal. The allocation information may include timeslot and code information of allocation to other mobile terminals. Some embodiments of the present invention facilitate a mobile terminal's ability to receive and demodulate a signal containing multiple interfering signals by communicating codes allocated to other mobile terminals.
Abstract:
A base station communicates with a user device in the mode of time division duplexing based on the orthogonal frequency division multiplexing scheme. The physics transmission resource used for communicating between the station and device is divided into a plurality of continuous frames in the time domain, each containing a plurality of sub-frames. The base station can include: a period determination device, for determining the period of the current frame, composed of a predetermined number of frames in a plurality of frames; a judgment device, for determining whether each sub-frame in the current frame is marked as the first or second state; a communication control device, for permitting the base station to communicate with the user device on the sub-frame when it is in the first state, forbidding communication only concerned with the user device performed by the base station on the sub-frame when it is in the second state.
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.
Abstract:
Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: 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 modulating a first carrier of the plurality of spectrally overlapping carrier signals based on a first modulation scheme while modulating a second carrier of the plurality of spectrally overlapping carrier signals based on a second modulation scheme.
Abstract:
A base station communicates with a user device in the mode of time division duplexing based on the orthogonal frequency division multiplexing scheme. The physics transmission resource used for communicating between the station and device is divided into a plurality of continuous frames in the time domain, each containing a plurality of sub-frames. The base station can include: a period determination device, for determining the period of the current frame, composed of a predetermined number of frames in a plurality of frames; a judgment device, for determining whether each sub-frame in the current frame is marked as the first or second state; a communication control device, for permitting the base station to communicate with the user device on the sub-frame when it is in the first state, forbidding communication only concerned with the user device performed by the base station on the sub-frame when it is in the second state.
Abstract:
Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising spectrally overlapping carrier signals from at least two of a plurality of remotes, wherein the spectrally overlapping carrier signals are modulated using an inverse Fourier transform algorithm; a transmitter; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; a controller programmed to calculate an elapsed time for each of the two remotes, the elapsed time representing a time between transmitting a ranging signal to a remote and receiving a signal from the remote in response to the ranging signal; the controller further programmed to reducing any difference between at least two elapsed times by instructing at least one of the plurality of remotes to adjust a delay.
Abstract:
A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system is provided. The system includes a plurality of remote units and a host unit that includes a demodulator. Each of the remote units transmits an upstream OFDM signal using a multiple access scheme to the host unit demodulator using at least one of a plurality of orthogonal tones within an OFDM waveform. The host unit receives the upstream OFDM signals from a plurality of the remote units. Portions of upstream OFDM signals from at least two of the remote units arrive at the host unit at the same time. The host unit demodulator demodulates the portions and the upstream signals from the plurality of remote units arrive at the host unit synchronized in time and frequency within the OFDM waveform.
Abstract:
A method and apparatus are disclosed to enable user equipment in a TD-SCDMA network to reduce or eliminate RF signal leakage from a transmitter to a receiver. In an aspect of the disclosure, a method includes receiving an assignment of an uplink time slot of a sub-frame and receiving an assignment of a downlink time slot of the sub-frame, wherein the uplink time slot is prevented from being sequential to the downlink time slot. In another aspect of the disclosure, a method includes receiving an assignment of an uplink time slot of a sub-frame associated with a first carrier frequency and receiving an assignment of a down-link time slot of a sub-frame associated with a second carrier frequency, wherein the first carrier frequency is prevented from being the same frequency as the second carrier frequency when the uplink time slot is sequential to the downlink time slot.
Abstract:
The invention relates to a process for digital, bidirectional data transmission between a processing unit and a position encoder, as based on the transmission of frames of a predetermined bit length, such that each frame is provided with at least an initial bit length for the transmission of data from the processing unit to the position encoder and at least a second bit length for the transmission of data from the position encoder to the processing unit; and such that the frame is provided with a time slot in which data is neither transmitted from the processing unit to the position encoder nor from the position encoder to the processing unit. In the time slot a triggering signal (external sync signal) is transmitted from the processing unit to the position encoder and this triggers the acquisition of position data. In the first bit length, a clock signal for synchronizing the processing unit and the position encoder is transmitted from the processing unit to the position encoder, and after the acquisition of position data triggered by the external sync signal, the acquired position data is transmitted from the position encoder to the processing unit. Between the transmission of two successive external sync signals at least one additional position-data request signal (internal sync signal) is transmitted from the processing unit to the position encoder, and this signal triggers another acquisition of position data, which is followed by the transmission of the acquired position data from the position encoder to the processing unit.