A mobile station, operable in a mobil communication system that executes a location registration processing by using the channel quality of a base station and an information concerning a base station the mobile station includes a base station information memory unit for storing therein information concerning a plurality of base stations and an amount in which the channel quality of the base station is changed with time and a location judging unit for judging on the basis of the amount in which the base station information is changed with time and which is stored in the base station information memory unit whether or not location registration processing is to be executed indicating a location in service area. Whether the location registration processing is to be executed or not is determined in accordance with the moving speed of the mobile station, thereby limiting the occurrence of a location registration request which becomes invalid with a large possibility in a short period of time because the mobile station moves to another location registration area or to the calling area in a short period of time.

Mobile communication system and location registration method in mobile communication system

Wireless terminals, e.g., mobile nodes, receive, identify, and measure broadcast signals from a plurality of cells (see Figure 1). They determine relative transmission power relationships corresponding to the received measured signals and determine at least two channel gain ratios. A geographic area is determined corresponding to the obtained at least two channel gain ratios and information indicating the geographic region in which such gain ratios may be detected. Each cell's base station transmits broadcast signals, e.g., beacon signals, pilot signals, and/or assignment signals for one more carriers. Some base stations use multiple carriers at different power levels. Some adjacent cells use different power levels for the same carrier. This carrier diversity approach tends to reduce overall interference in the system, yet provides mobiles with a variety of different strength signals which may be monitored and which vary as a function of distance from the source transmitter.

Wireless terminal location using apparatus and methods employing carrier diversity

Electronic devices are be provided that contain wireless communications circuitry The wireless communications circuitry includes radio-frequency transceiver circuitry coupled to multiple antennas Signal strength measurements are gathered using the antennas and corresponding signal strength difference measurements are produced to reflect which of the antennas is exhibiting superior performing The signal strength difference measurements are filtered using time-based averaging filters with different speeds Corresponding filtered difference measurements are compared to antenna switching criteria such as antenna switching thresholds An antenna switching threshold is adjusted in real time based on computations of how much variation is exhibited as a function of time between the difference measurements filtered using the filters of different speeds In addition, information on device movement or other data may be used in making threshold adjustments

Antenna Switching System with Adaptive Switching Criteria

A control channel is searched for call waiting in a mobile station where the power supply for a receiving circuit is turned off during a break time of receiving level measurements, wherein in a first control channel selection mode, all the control channels are divided into a plurality of groups, the receiving levels of the control channels are measured group by group intermittently and sequentially. The intermittent measurement of these groups are repeated until a control channel having a receiving level equal to or greater than a first predetermined value is detected. When a receiving level equal to or greater than the first predetermined value is detected, the receiving levels of all the control channels are measured in a second control channel selection mode.

Method for searching a control channel in a mobile station

A received power preset value is varied in such a manner that SIR measured at the base station comes to coincide with the target value SIRt By varying the received power preset value, a cell zone of the base station varies so that the number of mobile stations connected with the base station increases or decreases thereby SIR at each base station approximating with each other As a result, deviation of communication quality is restricted so that efficiency of the system can be improved

Mobile communication system and transmission power control method for a base station therein

PURPOSE: To control the size of a radio zone by correcting a reception level from a base station with a correction value of a reception level informed from the base station to a mobile station and informing the threshold level of the reception level required to make communication from each base station to the mobile station. CONSTITUTION: A correction value is informed to a mobile station 4 with an informing signal informed from base stations 1, 2, 3. Moreover, a mobile station 4 reads the correction value with the informing signal from the base stations 1, 2, 3 and measures the reception level 11 of the base stations 1, 2, 3 and obtains the reception level 11 of the base stations 1, 2, 3 and a reception level 12 after the correction to the base stations 1, 2, 3 from the correction value with the calculation. It is regarded by the correction that the radio zones of the base stations 1, 2, 3 are changed automatically. Thus, the size of the zone is controlled by calculating the correction value at the mobile station 4. COPYRIGHT: (C)1991,JPO&Japio

Seizo Onoe

Papers

Mobile communication control method