If the radio portable information terminal detects the current battery capacity level and the receiving electrical field level and finds that these levels are sufficient to perform data transmission/reception, the radio portable information terminal formulates a data transmission/reception possible signal to send the data transmission/reception possible signal via a base station to the information network center, which then checks to see that the radio portable information terminal is in the transmission/reception enabling state to perform data transmission/reception with the radio portable information terminal. To provide a system in which, when data transmission/reception is to be carried out between a radio portable information terminal and an information network center, the operation for checking the possible battery-off state or the intensity of the receiving electrical field, so far felt to be necessary, can be eliminated to render it possible to recognize the state of the radio portable information terminal at the information network center side.
Battery operated user equipment is disclosed for use in a radio telecommunications network, including means for monitoring the state of charge of the battery and means for communicating state of charge data to a base station during call set up.The battery data can be used to inform a caller that, for example, a called user's apparatus has reduced or limited battery capacity and thus that the expected duration of a call is limited.
A data delivery terminal (12) is connected to a delivery server (18) via a radio base station (14) and a cellular phone network (16). A user can input reservation information of content data (music data) by operating an operation panel on the data delivery terminal (12). For example, the reservation information includes a date and time of download and a title name of music data, connection information (DAP-TEL) to an access point (DAP) for a download server (20) and etc. When such the reservation information is input, the data delivery terminal (12) dials the access point in accordance with the date and time included in the reservation information. When a connection state is established, desired music data is transmitted from the download server (20) such that the music data is downloaded to a memory card attached to the data delivery terminal (12).
A data traffic is monitored, and the current traffic state is checked. If the traffic exceeds a threshold a, the time interval of Inquiry Scan is set to a maximum value X1 to prevent communication performance from deteriorating due to Inquiry Scan. Likewise, if the traffic falls in the range of the threshold a to a threshold b, the time interval of Inquiry Scan is set to an intermediate value X2. If the traffic amount is equal to or less than the threshold b, the time interval of Inquiry Scan is set to a minimum value X3.
When gateway server 30 receives an email, which is addressed to mobile station 10, gateway server 30 transmits an email arrival notice to mobile station 10. When gateway server 30 receives an acknowledgement response (referred to as `Ack` hereinafter) responding to the email arrival notice from mobile packet communication network 20, gateway server 30 evaluates the status of mobile station 10 on the basis of the type of Ack, and determines whether to transmit the email or not. Moreover, gateway server 30 modifies the time interval for retransmitting the email arrival notice to mobile station 10 according to the status of mobile station 10 when the transmission of the email arrival notice fails.
A method for data exchange with a mobile asset including the step of comparing the quality of the communication link to a predetermined value prior to initiating the communication. Polling of a fleet of mobile assets may be scheduled by considering a map of the communication link quality along the route of the mobile assets. An optimal packet size may be selected for the data transfer by considering the quality of the communication link.
