Abstract: In a handover control apparatus, a terminal is wirelessly connected with one of base stations to establish a wireless data communications connection. The terminal executes a handover process using a handover process section when an electric wave state becomes lower than a threshold value, which is variable. The threshold value can be adjusted according to a moving speed of the terminal. Furthermore, the threshold value is corrected according to the past electric wave state. The threshold value is corrected according to a difference of (i) a minimum electric wave state in a preceding handover process, and (ii) a lower limit. The correction is executed so as to reduce an excessive decline of an electric wave state in a succeeding handover process. Deterioration of a communications quality during a handover process can be thereby suppressed.

Abstract: A handover control apparatus selects, as a target station, an adjacent station having an upturn and stable transition trend of reception level of a radio wave received by a radio, when necessity to carry out handover is determined, and performs handover for switching from a serving station to the target station when the transition trend of the reception level of the received radio wave from the serving station is in a downturn trend and a calculation value of a serving station approximation equation is smaller than a calculation value of an adjacent station approximation equation at a determination timing.

Abstract: An in-vehicle antenna device includes: a dielectric element having a front surface, first and second side surfaces and a rear surface and including a power supply point on both the first and second side surfaces, a first conductive surface on the first side surface, a second conductive surface on the second side surface, and a third conductive surface on the rear surface; and an antenna element including a base element coupled with the power supply point at one corner of the front surface and a branch element connected to the base element and having an end. A part of the branch element moves apart from one of the first and second conductive surfaces as it goes from the base element to the one end of the branch element. The front surface is attached to a windshield of a vehicle.

Abstract: A handover control apparatus selects, as a target station, an adjacent station having an upturn and stable transition trend of reception level of a radio wave received by a radio, when necessity to carry out handover is determined, and performs handover for switching from a serving station to the target station when the transition trend of the reception level of the received radio wave from the serving station is in a downturn trend and a calculation value of a serving station approximation equation is smaller than a calculation value of an adjacent station approximation equation at a determination timing.

Abstract: In a handover control apparatus, a terminal is wirelessly connected with one of base stations to establish a wireless data communications connection. The terminal executes a handover process using a handover process section when an electric wave state becomes lower than a threshold value, which is variable. The threshold value can be adjusted according to a moving speed of the terminal. Furthermore, the threshold value is corrected according to the past electric wave state. The threshold value is corrected according to a difference of (i) a minimum electric wave state in a preceding handover process, and (ii) a lower limit. The correction is executed so as to reduce an excessive decline of an electric wave state in a succeeding handover process. Deterioration of a communications quality during a handover process can be thereby suppressed.

Abstract: An in-vehicle antenna device includes: a dielectric element having a front surface, first and second side surfaces and a rear surface and including a power supply point on both the first and second side surfaces, a first conductive surface on the first side surface, a second conductive surface on the second side surface, and a third conductive surface on the rear surface; and an antenna element including a base element coupled with the power supply point at one corner of the front surface and a branch element connected to the base element and having an end. A part of the branch element moves apart from one of the first and second conductive surfaces as it goes from the base element to the one end of the branch element. The front surface is attached to a windshield of a vehicle.

Abstract: It is determined whether each of several subcarriers has an adequate propagation characteristic in a first horizontally polarized wave antenna. Of the several subcarriers, a subcarrier, which is determined to have an adequate propagation characteristic in the first horizontally polarized wave antenna, is assigned with transmission data. A transmission signal containing the transmission data is thereby transmitted from the first horizontally polarized wave antenna. In addition, of the several subcarriers, a subcarrier, which is determined not to have an adequate propagation characteristic in the first horizontally polarized wave antenna, is also assigned with transmission data in either a second horizontally polarized wave antenna or a vertically polarized, wave antenna. A transmission signal containing the transmission data is thus transmitted from the second horizontally polarized wave antenna or the vertically polarized wave antenna.

Abstract: An on-board communication equipment on each of two vehicles receives a radio wave from two or more GPS satellites, and determines a carrier wave phase of the received radio wave. Then, the on-board communication equipment on one vehicle receives, from the other vehicle, information on the carrier wave phase observed in the other vehicle. Further, the on-board communication equipment calculates a relative position of a self vehicle relative to the other vehicle by a Carrier-Phase DGPS positioning based on a difference between two carrier wave phases (e.g., single difference, double difference or the like), that is, one from the self vehicle and one from the other vehicle, both having the same observation time, from among the available carrier wave phases.

Abstract: A planar antenna is disclosed. The planar antenna includes: a radiator element having a wideband resonant characteristic; and a parasitic element having a planar shape. The parasitic element has a first side, a second side, a third side and a fourth side. Each of the first side and the second side is parallel to a direction of an electric current to be excited in the radiator element. The first side is located closer to the radiator element than the second side is. The first side is shorter than the second side. The third side connects one ends of the first side and the second side. The fourth side connects the other ends of the first side and the second side. A region between the third and fourth sides tapers in a direction from the second side toward the first side.

Abstract: An on-board communication equipment on each of two vehicles receives a radio wave from two or more GPS satellites, and determines a carrier wave phase of the received radio wave. Then, the on-board communication equipment on one vehicle receives, from the other vehicle, information on the carrier wave phase observed in the other vehicle. Further, the on-board communication equipment calculates a relative position of a self vehicle relative to the other vehicle by a Carrier-Phase DGPS positioning based on a difference between two carrier wave phases (e.g., single difference, double difference or the like), that is, one from the self vehicle and one from the other vehicle, both having the same observation time, from among the available carrier wave phases.

Abstract: An antenna system for use in a wide frequency band has a reflection board that has a board shape with an outer edge and an inner edge. The antenna system connects the reflection board and an antenna module in a manner that does not allow a flow of a direct current. Further, a dimension of the reflection board along a polarization direction of the antenna module has a value that is equal to or greater than a product of a maximum wavelength of a usable frequency band multiplied by a wavelength reduction rate of a dielectric material.

Abstract: A vehicle device for use in vehicle-roadside communication that communicates with a roadside device disposed on a roadside includes a radio unit for receiving an informational message from the roadside device as well as a display and a speaker for information provision. The vehicle device further includes a storage unit for storing the informational message received by the radio unit. A system controller in the vehicle device determines whether information provision condition for providing the informational message in the storage unit is met based on an information content and current condition information in the informational message received by the radio unit. When the information provision condition is determined to be met, the system controller controls the display and the speaker to cause a provision of the informational message.

Abstract: A mobile communications terminal has a transmitter for transmitting a specific identification code of a reference base station as a time reference for network position determination. Therefore, a position server connected with a CDMA network can distinguish the reference base station from the other base stations regardless of positioning relationship between the mobile terminal and the base stations.

Abstract: A wireless terminal is designed to prevent the user from having to wait a long time in case fetching of search data takes a long time. The wireless terminal, if it determines the need of long time for the search of GPS satellites by a GPS transceiver, inhibits the GPS transceiver from searching GPS satellites and operates on a CDMA transceiver to search for CDMA base stations. The wireless terminal fetches only CDMA base station data pertinent to the CDMA base stations and sends to a position data server, and the position data server points the location of the wireless terminal based solely on the CDMA base station data provided by the wireless terminal. Based on the inhibition of search of GPS satellites by the GPS transceiver, the time needed until the reception of positioning result can be reduced, and the user is prevented from being subjected to long time waiting.

Abstract: In a mobile station, a period for receiving a GPS signal from a predetermined satellite based on data for satellite reception is set up by a timer, and the GPS signal whose reception level is higher than a threshold value is awaited. Until elapsed time reaches a preset time, indoor counter is incremented if the GPS signal is unable to be received or outdoor counter is incremented if the GPS signal is able to be received. When each counter reaches a specified value, each mode is determined. If the mode is different from a previous mode, a mode shift is executed and setups of user interfaces, display, speaker and others, are altered for the updated mode, indoor or outdoor.

Abstract: A mobile communication terminal stores positioning information including global positioning system signals and base station information required by a position server in a communication network to calculate the terminal position. When the position server calculates the terminal position based on these positioning unit information, the position information is not reported to the user if the indefinite information equivalent to a positioning error contained in the average value calculated for the terminal position information exceeds a predetermined threshold value. When the average processing count exceeds a maximum positioning count, that average value is reported to the user.

Abstract: A radio communication terminal is used in a position specifying system, in which both retrieval timing and retrieval time of each of GPS satellites are received via a communication base station from a position information server. The position information server specifies a position of the radio communication terminal based upon at least GPS satellite information received from the radio communication terminal. The radio communication terminal corrects at least any one of both retrieval timing and retrieval time so that the retrieval timing is moved, or the retrieval time is prolonged. The radio communication terminal retrieves the GPS satellites based upon the corrected retrieval timing and the corrected retrieval time.

Abstract: A mobile station requests a start of positioning and receives a response of positioning from a positioning server, following which it informs the positioning server of its own station information and neighboring base station information gathered through searching the neighboring base stations. Thereby, the mobile station receives assistant information regarding GPS satellites to be captured based on a station location designated by the positioning server and then it measures a GPS signal and a base station signal such as an apparent signal delay. In the case that the positioning information collected as described above is sufficient for location computing, it displays the location computed by the positioning server. In contrast, in the case that the positioning information is insufficient, it displays “positioning impossible” without sending the positioning information to the positioning server.

Abstract: A PDC/PHS phone has both PDC communication function and PHS communication function. The PDC/PHS phone switches its communication mode from a PDC communication to a PHS communication which is less power consuming than the PDC communication, when its built-in battery runs down to a reference level in the course of communication with another phone. The PDC/PHS phone switches its communication mode back to the PDC communication again, when the battery is recharged enough.

Abstract: A cellular phone receives a position measurement result, which indicates a position of the cellular phone determined based on both GPS satellite information and CDMA base station information, from a location information server. Then, when a value indicated by uncertainty information of the position measurement result is greater than a first threshold value, the cellular phone receives another position measurement result, which indicates the position of the cellular phone determined based only on the CDMA base station information, from the location information server and displays it on a display device.