摘要:
Provided is a wireless relay system that improves system throughput between terminal stations and flexibly makes system throughput variable with respect to short-term traffic fluctuations. In the wireless relay system, a plurality of relay stations relay communication between two terminal stations that perform random access. The terminal stations and the relay stations include a slot synchronization unit, a time synchronization unit, and a transmission unit. The slot synchronization unit synchronizes slot timing of a time slot indicating a unit time. The time synchronization unit performs time synchronization for synchronization of the slot timing. The transmission unit transmits a transmission packet to a wireless line in synchronization with the slot timing. A transmission right is allocated for at least one time slot to each of a plurality of groups which are configured so that a group of a terminal station or a relay station and a group of an adjacent terminal station or an adjacent relay station are different from each other. The transmission unit transmits the transmission packet to the wireless line only in a time slot in which the transmission right is allocated to the group to which the terminal station or the relay station belongs.
摘要:
Provided is a wireless relay system that improves system throughput between terminal stations and flexibly makes system throughput variable with respect to short-term traffic fluctuations. In the wireless relay system, a plurality of relay stations relay communication between two terminal stations that perform random access. The terminal stations and the relay stations include a slot synchronization unit, a time synchronization unit, and a transmission unit. The slot synchronization unit synchronizes slot timing of a time slot indicating a unit time. The time synchronization unit performs time synchronization for synchronization of the slot timing. The transmission unit transmits a transmission packet to a wireless line in synchronization with the slot timing. A transmission right is allocated for at least one time slot to each of a plurality of groups which are configured so that a group of a terminal station or a relay station and a group of an adjacent terminal station or an adjacent relay station are different from each other. The transmission unit transmits the transmission packet to the wireless line only in a time slot in which the transmission right is allocated to the group to which the terminal station or the relay station belongs.
摘要:
The receiving device receives a transmitted signal from a transmitting device by dividing by N the spectrum of a signal to be transmitted and performing spectrum editing to reduce its occupied bands. The receiving device generates a first decoded signal by error-correcting and decoding this received signal in the bandwidth of the signal to be transmitted, and generates a transmission replica signal from this first decoded signal and divides by N the spectrum of this transmission replica signal to generate N sub-replicas. The receiving device generates a compensated received signal by restoring the spectrum of the signal to be transmitted from the transmitting device using the N sub-replicas and the received signal, and decodes this compensated received signal to generate a second decoded signal.
摘要:
Provided is a wireless communication system employing network coding which can set transmission quality for each destination of packets and improve throughput. The wireless communication system is provided with a wireless relay station apparatus and wireless terminal station apparatuses. The wireless relay station apparatus selects coding rates to be used for a first packet and a second packet in accordance with communication quality required for the first packet and the second packet, generates error correction encoded packets having the same data length from the first packet and the second packet using the selected coding rates, performs network encoding on the error correction encoded first and second packets to generate a network encoded packet, and transmits the generated network encoded packet. The wireless terminal station apparatus performs error correction encoding on a third packet equal to one of the first and second packets, performs network decoding on a received network encoded packet using the error correction encoded third packet to generate a decoded packet, and performs error correction decoding.
摘要:
A communication terminal used in a mobile communication system complying with a carrier sense multiple access scheme is disclosed. The communication terminal includes: a receiving unit configured to receive a wireless packet transmitted by another communication terminal or a base station; a determination unit configured to determine periodic transmission timing of the communication terminal based on determination criterion information included in the wireless packet; and a transmission unit configured to periodically transmit wireless packets to the base station based on the transmission timing.
摘要:
In a mobile communication system, multiple transceivers perform radio communications in the same frequency band. A transceiver (700) comprises a first sync timing detection part (706) configured to detect sync timing for a desired signal transmitted from a counterpart transceiver; a second sync timing detection part (708, 710) configured to detect sync timings for one or more undesired signals from non-counterpart transceiver(s); an error information determination part (712) configured to determine error information based on the sync timings for the desired and undesired signals; a signal generating part (714) configured to generate a feedback signal containing the error information; a transmission timing determination part (722) configured to update transmission timing for a transmission signal including the feedback signal according to a control signal received from the counterpart transceiver; and a transmission part (736) configured to transmit the transmission signal to the counterpart transceiver according to the updated transmission timing.
摘要:
A frequency band allocation device is disclosed. The frequency band allocation device comprises a frequency band selection unit (1161, 1162) for selecting usable frequency bands from a dedicated frequency band, a registered frequency band and an unlicensed frequency band; and a frequency band allocation unit (1163) for allocating a frequency band out of the selected usable frequency bands to an uplink and downlink, so as to satisfy user required QoS.
摘要:
An OFDM receiver includes a timing error detection unit that determines error information based on a difference between receiving timing of a desired signal from a counterpart transmitter and receiving timing of an undesired signal from a non-counterpart transmitter. The timing error detection unit includes a pilot signal detection unit configured to detect a pilot signal of the desired signal and a pilot signal of the undesired signal from an FFT-processed received signal; a first converting unit configured to convert a frequency-domain channel estimate derived from the pilot signal of the desired signal to a first time-domain channel impulse response; a second converting unit configured to convert a frequency-domain channel estimate derived from the pilot signal of the undesired signal to a second time-domain channel impulse response; and an error information determination unit configured to determine the error information based on the first and second channel impulse responses.
摘要:
When OFDM signals are transmitted from a plurality of antennas, a pilot carrier is transmitted from one antenna among the plurality of antennas, and a null signal is transmitted from an antenna other than that antenna by a subcarrier of the frequency band that transmits the pilot carrier.
摘要:
A base station that communicates with a mobile station includes: a storing unit for storing a predetermined number of base station information, each including a base station ID for discriminating a specific base station and parameter information for radio communications set for the specific base station; an acquisition unit for acquiring a base station ID of other base stations forming a destination cell of the mobile station, or a base station ID of other base station forming a source cell of the mobile station; an aggregating unit for aggregating the number of times that each of the base station IDs is acquired in a first time period; a determination unit for determining a priority of each of the base station IDs on the basis of the aggregated results of the acquisition numbers; a judging unit for judging whether or not there is a base station ID which has a priority higher than the base station ID stored in the storage, and whose acquisition number is larger than a predetermined number of times; and a manager for deleting, from the storage, a base station information including a base station ID having a priority lower than the base station ID judged to have a higher priority, and for storing, in the storage, a base station information including the base station ID judged as to have the higher priority, in a case where the judging unit judges there is the base station ID having a higher priority and whose acquisition number is larger.