Abstract: An information distribution apparatus includes an obstacle identification apparatus that identifies an obstacle to a vehicle traveling in an area and then outputs obstacle information related to the position of the obstacle, a road database representing the positions of roads, and an impassable-road determination means that determines a road through which the vehicle cannot pass, based on the obstacle information outputted from the obstacle identification apparatus and the road database, and then outputs impassable-road information. A narrow-area automatic driving system is provided with the information distribution apparatus and the vehicle that travels from a departure point to a target point, along a route formed based on information outputted from the information distribution apparatus.

Abstract: An RF unit receives predetermined signals. The RF unit amplifies the received signals. A gain control unit controls the gain at the RF unit based on the amplified signal and has the RF unit use the controlled gain. The gain control unit performs different controls on the received signals, depending on the case when the received signal is a known signal placed in the beginning of packet signal and the case when the received signal is a signal other than the packet signal.

Abstract: A control information extraction unit receives information on a frame that contains at least a plurality slots from an access control apparatus for controlling communications between radio apparatuses. The control information extraction unit generates a frame that contains at least a plurality of slots in such a manner as to synchronize with the frame corresponding to the received information. An estimation unit estimates empty slots in the plurality of slots generated. A selection unit selects, at random, at least one of the estimated. A modem unit and the like broadcast data using the selected slot.

Abstract: An RF unit receives predetermined signals. The RF unit amplifies the received signals. A gain control unit controls the gain at the RF unit based on the amplified signal and has the RF unit use the controlled gain. The gain control unit performs different controls on the received signals, depending on the case when the received signal is a known signal placed in the beginning of packet signal and the case when the received signal is a signal other than the packet signal.

Abstract: An RF unit receives predetermined signals. The RF unit amplifies the received signals. A gain control unit controls the gain at the RF unit based on the amplified signal and has the RF unit use the controlled gain. The gain control unit performs different controls on the received signals, depending on the case when the received signal is a known signal placed in the beginning of packet signal and the case when the received signal is a signal other than the packet signal.

Abstract: It is specified that a frame containing at least the plurality of slots is repeated. A detecting unit detects a slot usable in the communications between terminal apparatuses, from among a plurality of slots. A modem unit and an RF unit broadcast the information on the detected slot. A power measuring unit in the detecting unit measures the respective received powers of the plurality of slots, and an empty slot identifying unit identifies a slot whose received power is less than a threshold value.

Abstract: A control information extraction unit receives information on a frame that contains at least a plurality slots from an access control apparatus for controlling communications between radio apparatuses. The control information extraction unit generates a frame that contains at least a plurality of slots in such a manner as to synchronize with the frame corresponding to the received information. An estimation unit estimates empty slots in the plurality of slots generated. A selection unit selects, at random, at least one of the estimated. A modem unit and the like broadcast data using the selected slot.

Abstract: A control information extraction unit receives information on a frame that contains at least a plurality slots from an access control apparatus for controlling communications between radio apparatuses. The control information extraction unit generates a frame that contains at least a plurality of slots in such a manner as to synchronize with the frame corresponding to the received information. An estimation unit (82) estimates empty slots in the plurality of slots generated. A selection unit selects, at random, at least one of the estimated. A modem unit and the like broadcast data using the selected slot.

Abstract: It is specified in a manner such that a frame containing a first period formed by a plurality of slots and a second period having a predetermined length is repeated. A detecting unit detects a slot, which is usable for the communications between a plurality of other terminal apparatuses, from among a plurality of slots in the first period of a frame containing the first period and the second period. A modem unit and an RF unit broadcast information on the detected slot.

Abstract: A detector receives detects a first known signal in a packet signal. An LTF correlation unit performs correlation processing on the packet signal received by a receiving unit. Upon detecting the arrival timing, an update correlation unit terminates a first window and performs correlation processing on the packet signal received by the receiving unit, in a second window. When correction timing is detected and when correction timing is more likely to be accurate than the arrival timing, an estimation unit changes the correction timing to the arrival timing; when the arrival timing is more likely to be accurate than the correction timing, the estimation unit maintains the arrival timing.

Abstract: Preceding filters receive the inputs of a plurality of received signals associated respectively with a plurality of antennas. Subsequent filters band-limit the plurality of inputted received signals, respectively. A first combining unit derives a weight vector for the plurality of band-limited received signals and performs array synthesis on the plurality of band-limited received signals, using the derived weight vector. The second combining unit performs array synthesis on the plurality of inputted received signal signals, using the derived weight vector. A demodulator demodulates the array-synthesis result.

Abstract: A control unit allocates sequentially a channel for use in data transmission and a channel for use in channel estimation used to acquire channel characteristics between a radio apparatus and another radio apparatus to be communicated with, to the another radio apparatus. A radio unit to an IF unit communicate with the another radio unit through the sequentially allocated data transmission channels, respectively. An acquisition unit acquires the traveling speed of the another radio apparatus in communication with the radio apparatus. A decision unit varies the frequency at which the channel for use in channel estimation is allocated, based on the traveling speed acquired.

Abstract: A measuring unit measures a quality of a received packet signal. An estimating unit estimates entry from a second area to a first area when the measured quality is improved so as to satisfy a first condition and estimates the entry from the first area to the second area when the quality measured by the measuring unit is deteriorated so as to satisfy a second condition. The estimating unit sets different values for a parameter included in the first condition and the parameter included in the second condition. The determining unit determines a first period or a second period as transmission timing based on an estimated result.

Abstract: A control information extraction unit receives information on a frame that contains at least a plurality slots from an access control apparatus for controlling communications between radio apparatuses. The control information extraction unit generates a frame that contains at least a plurality of slots in such a manner as to synchronize with the frame corresponding to the received information. An estimation unit (82) estimates empty slots in the plurality of slots generated. A selection unit selects, at random, at least one of the estimated. A modem unit and the like broadcast data using the selected slot.

Abstract: A frame specifying unit frames in such a manner that a frame containing at least a plurality of slots is repeated and in such a manner that a part of the plurality of slots contained in each frame are reserved for use on an access control apparatus. An empty slot identifying unit detects a slot, which is usable for the communications between radio apparatuses, from among the remaining part of the plurality of slots. A selection unit selects a slot from among the part of the plurality of slots in order to broadcast information on the detected slot. A modulation unit and an RF unit broadcast information on the slot detected by the empty slot identifying unit, using the selected slot.

Abstract: It is specified in a manner such that a frame containing a first period formed by a plurality of slots and a second period having a predetermined length is repeated. A detecting unit detects a slot, which is usable for the communications between a plurality of other terminal apparatuses, from among a plurality of slots in the first period of a frame containing the first period and the second period. A modem unit and an RF unit broadcast information on the detected slot.

Abstract: It is specified that a frame containing at least the plurality of slots is repeated. A detecting unit detects a slot usable in the communications between terminal apparatuses, from among a plurality of slots. A modem unit and an RF unit broadcast the information on the detected slot. A power measuring unit in the detecting unit measures the respective received powers of the plurality of slots, and an empty slot identifying unit identifies a slot whose received power is less than a threshold value.

Abstract: A control unit allocates sequentially a channel for use in data transmission and a channel for use in channel estimation used to acquire channel characteristics between a radio apparatus and another radio apparatus to be communicated with, to the another radio apparatus. A radio unit to an IF unit communicate with the another radio unit through the sequentially allocated data transmission channels, respectively. An acquisition unit acquires the traveling speed of the another radio apparatus in communication with the radio apparatus. A decision unit varies the frequency at which the channel for use in channel estimation is allocated, based on the traveling speed acquired.

Abstract: Preceding filters receives the inputs of a plurality of received signals associated respectively with a plurality of antennas. Subsequent filters band-limit the plurality of inputted received signals, respectively. A first combining unit derives a weight vector for the plurality of band-limited received signals and performs array synthesis on the plurality of band-limited received signals, using the derived weight vector. The second combining unit performs array synthesis on the plurality of inputted received signal signals, using the derived weight vector. A demodulator demodulates the array-synthesis result.