Abstract:
PROBLEM TO BE SOLVED: To provide a radio communication system for optimizing the length of a preamble according to variation and propagation environment of each device and improving transmission efficiency of data. SOLUTION: When synchronization is established with the length of the initial synchronization symbol, the preamble for synchronization is sequentially shortened for every super frame and it is determined that immediately before synchronization is disabled, the optimum length of the preamble for synchronization is obtained. When the synchronization can not be established with the length of the initial synchronization symbol, the preamble (SYNC) for synchronization is sequentially increased for every super frame, and when the synchronization is enabled, it is determined that the optimum length for the preamble for synchronization can be obtained. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a data communication system which can obtain an LLR (log-likelihood ratio) by correctly estimating a channel gain and noise variance without increasing overhead, and can execute decoding processing. SOLUTION: The data communication system has a structure in which a unique word is added to a data block and transmitted so as to configure an FFT block, a unique word added to the data block in the FFT block among signals added as guard interval is not removed but used to equalize frequency domain together with data, an LLR is obtained using the unique word received after equalization processing in the frequency domain, and the LLR is used to perform decode processing of LDPC (low density parity check codes). COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a radio communication system, in which a time for facing the antenna of a control terminal to a dependent terminal is shortened when there is a communication request whereby communication between the control terminal and the dependent terminal can be started in a short time. SOLUTION: The control terminal transmits beacon at a predetermined time to respective predetermined directions and the dependent terminal transmits a member registering demand to the control terminal upon receiving the beacon at the predetermined time in the predetermined direction while the control terminal receives the member registering request and determines an orientation capable of communicating to register in a terminal registration table and, thereafter, when there is the communication request from the dependent terminal, communication is effected between the dependent terminal based on an inclination information registered in the terminal registration table of the control terminal. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a radio terminal for flexibly handling channel equalization in time domain and in a frequency domain. SOLUTION: A preamble generation section 25 generates a preamble to be added to a radio frame. The preamble generation section 25 adds a pattern at the rear of a code of a sequence to the front side of a pattern of the code of the series as a margin, and adds a pattern at the front of the code of the sequence to the rear side of the pattern of the code of the series as a preamble CE for estimating channels, thus generating a preamble for maintaining code continuity. By using such a preamble, the channels in time domain and in frequency domain are appropriately estimated. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a method and a system for quickly matching antenna directivity between terminal devices in a wireless personal area network (PAN). SOLUTION: In a communicating system which performs wireless communication between a control terminal 1 and one or more subordinate terminals 2 each having an antenna, the control terminal 1 includes a first beam transmitting and receiving direction controller 13 which controls transmitting and receiving directions of an antenna beam, a beacon transmitter 15 which transmits beacon, and an acknowledge (ACK) receiver 16 which receives an ACK signal, and the subordinate terminal 2 includes a second beam transmitting and receiving direction controller 23 which controls the transmitting and receiving directions of the antenna beam, a beacon receiver 27 which receives the beacon from the control terminal, and an ACK transmitter 28 which transmits the ACK signal. The whole directional ranges of an antenna 1A of the control terminal 1 and an antenna 2A of the subordinate terminal 2 are divided gradually. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a radio terminal capable of generating a preamble and a known pattern in the case of reception without using a plurality of pattern generating circuits. SOLUTION: A pattern generating section 25 has a Golay code generating section 51, and can generate patterns corresponding to parameters. The preamble (SYNC) for synchronism and the preamble (CE) for estimating a channel are generated by the patterns from the pattern generating section 25 in the case of transmission. The known patterns for the synchronism, for an AFC and for equalizing the channel or the like can be generated from the pattern generating section 25 in the case of the reception. Since the pattern generating section 25 can generate various patterns corresponding to the parameters, a plurality of the pattern generating circuits are made unnecessary. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a radio terminal for flexibly handling channel equalization in time domain and in frequency domain. SOLUTION: A subblock generation section 23 is provided. The subblock generation section 23 divides a transmission symbol into a prescribed number of information symbols. A symbol at the rear of the information symbol is added to the head of the prescribed number of information symbols as a cyclic prefix. When the symbol at the rear of the information symbol is added to the head of the prescribed number of information symbols as the cyclic prefix to compose a subblock, the continuity of symbols is maintained, thus reliably equalizing the channel in frequency domain. COPYRIGHT: (C)2009,JPO&INPIT