摘要:
Multi-carrier transmission is performed without inserting a repetitive signal into guard interval periods. A transmitter provides guard interval periods by using a null signal to save transmission power and prevent the deterioration of the SN ratio. Delayed waves at the head of each received symbol cause high-frequency waves to occur and carriers to interfere with one another. Accordingly, a receiver adds a component following each received symbol to a delayed-wave component at the head of the received symbol. As a result, the delayed-wave component at the head of the received symbol and the added component become continuous in wave form and subcarriers do not interfere with each other.
摘要:
Multi-carrier transmission is performed without inserting a repetitive signal into guard interval periods. A transmitter provides guard interval periods by using a null signal to save transmission power and prevent the deterioration of the SN ratio. Delayed waves at the head of each received symbol cause high-frequency waves to occur and carriers to interfere with one another. Accordingly, a receiver adds a component following each received symbol to a delayed-wave component at the head of the received symbol. As a result, the delayed-wave component at the head of the received symbol and the added component become continuous in wave form and subcarriers do not interfere with each other.
摘要:
A radio communication device has a first transmission and reception circuit for transmitting and receiving a channel which is established in a first occupied frequency band according to a first access process, and a second transmission and reception circuit for transmitting and receiving a channel which is established in a second occupied frequency band which is established in a guard band in the first occupied frequency band according to a second access process.
摘要:
Multi-carrier transmission is performed without inserting a repetitive signal into guard interval periods. A transmitter provides guard interval periods by using a null signal to save transmission power and prevent the deterioration of the SN ratio. Delayed waves at the head of each received symbol cause high-frequency waves to occur and carriers to interfere with one another. Accordingly, a receiver adds a component following each received symbol to a delayed-wave component at the head of the received symbol. As a result, the delayed-wave component at the head of the received symbol and the added component become continuous in wave form and subcarriers do not interfere with each other.
摘要:
Multi-carrier transmission is performed without inserting a repetitive signal into guard interval periods. A transmitter provides guard interval periods by using a null signal to save transmission power and prevent the deterioration of the SN ratio. Delayed waves at the head of each received symbol cause high-frequency waves to occur and carriers to interfere with one another. Accordingly, a receiver adds a component following each received symbol to a delayed-wave component at the head of the received symbol. As a result, the delayed-wave component at the head of the received symbol and the added component become continuous in wave form and subcarriers do not interfere with each other.
摘要:
In a radio communication such as a radio telephone system or the like, a transmission channel which can accommodate a change in a transmission capacity is set. While a terminal apparatus and a base station are in communication for transmitting a predetermined information using a predetermined transmission channel, a signal requesting to set another transmission channel is transmitted using a part of the predetermined transmission channel to initiate communication between the terminal apparatus and the base station through the other transmission channel.
摘要:
In order cope with a change of the transmitting capacity in a wireless telephone system. A number of transmission channels are set within the transmission frequency band prepared for each base station. When a communication is made between the terminal equipment and the base station through the transmission channels, at least a first transmission channel and a second transmission channel are set as the transmission channel depending on a class of information to be transmitted. The first transmission channel is set to have a fixed transmitting capacity and the second transmission channel is set so that the minimum transmitting capacity may be defined and the transmitting capacity greater than the minimum transmitting capacity may be set depending on the setting condition of the transmission channels within the transmission frequency band prepared.
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.