摘要:
A time slot which is formed by time-division multiplexing is divided into a plurality of blocks in at least a frequency direction, and also within each one of said plurality of blocks a plurality of subcarriers are formed. A predetermined number of plurality of blocks forms one communication channel, whereby a plurality of communications are formed within a time slot. With this, one time slot can be multiplexed by communication of multiple carriers separated in frequency. In this manner, with simple constitution, communication can be performed satisfactorily even in an environment where a multiple path is present.
摘要:
A transmitting apparatus, a receiving apparatus, and a communication system are provided that allow a reduction in a frame loss due to interference caused by use of the same channel. A transmitting apparatus disposed in a base station includes a GPS receiver for receiving a GPS signal, a timing generator for controlling respective function blocks in accordance with the GPS signal and an inter-base-station control signal so as to precisely synchronize the timing of frame transmission among base stations, the front-end transmission processing unit including for converting transmission information into transmission time slots, a frame generator for generating a frame including a plurality of time slots and one frame guard, and a back-end transmission processing unit for transmitting the generated frame as a radio signal.
摘要:
The present invention eliminates a transmission-waiting operation which is unnecessary while accommodating a prioritized traffic. Although a communication station enters a transmission-disallowed state in response to detection of a signal addressed to another station in accordance with medium access control based on CSMA, if the communication station receives a frame transmitted with priority to a local station during the transmission waiting, it cancels the transmission-disallowed state, sends back a frame responding the frame transmitted with priority and effectively operates a transmission prioritized period. The communication station starts a search procedure to perform a processing of evading duplication of the transmission prioritized periods if it judges a possibility of a problem occurring in a time zone in which reception with priority is possible.
摘要:
There is provided a communication apparatus compliant with ultra wide band communication systems for improving resistance to interfering waves in combination with DS-SS (direct sequence spread spectrum). There is provided a training section based on short code spread with the same pattern repeated for each symbol length. Actual communication itself is preceded by coherent channel measurement of a transmission channel by using the training section to specify a length of the short code to be a measurement period and using N cycles of a carrier as a time resolution for measurement. A chip timing is controlled at the time resolution for measurement. At all points given by a time resolution for a measurement period, a measured value is obtained by using the short code to despread A/D-converted values from an input signal based on the chip timing.
摘要:
A sound processing apparatus includes a power spectrum operation unit obtaining a power spectrum of an audio signal, an envelope component removal unit removing an envelope component of the power spectrum and generating a signal characteristic that represents a peakness of the power spectrum, a filter characteristic calculation unit calculating a filter characteristic suppressing the signal characteristic by using the signal characteristic, and a suppress filter filtering the audio signal by using the filter characteristic.
摘要:
Disclosed is a method that preferably performs transmission processing to a time sequence signal of a known pattern as the pre-amble and an OFDM transmitted signal.In data communications, the general practice defines the pre-amble and detects the peaks of the mutual correlation to thereby detect synchronization. The pre-amble here is defined by the binary value in most cases for simplification of a correlation detecting device. In this case, the spectrum becomes irregular with sharp peaks and dips, which deteriorates the correlation characteristic. The method of the invention forcibly adjusts the spectrum amplitude of the pre-amble pattern on the transmitting side while retaining the phase information thereof, and thereby the method improves the spectrum and correlation characteristics while securing simplification of a correlation detecting device on the receiving side.
摘要:
Remote control data is securely transmitted to a device under control. A remote control device transmits an acknowledge request for A ch to the device under control (S21). When the device under control has assigned A ch as the reception channel, acknowledge ACK is received. A ch is assigned as the transmission channel (S23), and a command frame is transmitted through A ch (S24). When acknowledge ACK has not been received, an acknowledge request for B ch is transmitted to the device under control (S25). When the device under control has assigned B ch as the reception channel, acknowledge ACK is received. B ch is assigned as the transmission channel (S27), and a command frame is transmitted through B ch (S28). The remote control device can transmits a command through a channel through which the device under control can receive the command, so that secure remote control can be accomplished.
摘要:
Channel characteristics need to be estimated in a wireless communication system which performs frequency hopping. A transmission side aligns phase values of carriers of frequencies used for hopping to known values at a transmission start time and transmits a transmission signal for each hopping obtained by converting frequencies. A reception side aligns phase values of carriers of frequencies used for each hopping at a reception start time and performs frequency conversion for respective reception signals. A phase rotation component contained in the reception signal for each hopping is common to all hoppings. Consequently, the phase rotation component can be included in channel characteristics to be measured for estimation.
摘要:
A reference frequency of 4224 MHz is divided into ½ to obtain a sampling frequency of 2112 MHz, and further the frequency division into ½ is sequentially performed and the values of three bits outputted by the ½, ¼ and ⅛ frequency division are decoded in response to frequency selection. From one set of nonlinear 2-bit DA converters which output amplitudes {−1.7, −0.7, 0.7, 1.7} using these decoded values as input, complex amplitudes corresponding to eight phases in a complex plane are outputted, so that complex sine waves are generated. Using these complex sine waves, the frequency switching is performed. Center frequencies of respective bands can be obtained without a phase error or an amplitude error.
摘要:
Disclosed is a method that preferably performs transmission processing to a time sequence signal of a known pattern as the pre-amble and an OFDM transmitted signal.In data communications, the general practice defines the pre-amble and detects the peaks of the mutual correlation to thereby detect synchronization. The pre-amble here is defined by the binary value in most cases for simplification of a correlation detecting device. In this case, the spectrum becomes irregular with sharp peaks and dips, which deteriorates the correlation characteristic. The method of the invention forcibly adjusts the spectrum amplitude of the pre-amble pattern on the transmitting side while retaining the phase information thereof, and thereby the method improves the spectrum and correlation characteristics while securing simplification of a correlation detecting device on the receiving side.