Source: http://www.google.com/patents/US6708030?dq=inventor:%22Arthur+R.+Hair%22&ei=VAy0Tsa4NYTl0QGQiqWiBA
Timestamp: 2014-03-17 17:15:12
Document Index: 267280773

Matched Legal Cases: ['art 1', 'art 1', 'art 2', 'art 2', 'art 3', 'art 3', 'art 4', 'art 4', 'art 5', 'art 5']

Patent US6708030 - Selection method of a handoff system in a CDMA mobile communication system - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA selection method of a handoff system in a CDMA radio data communication system, which is capable of selecting one of a hard handoff system and a soft handoff system depending on situations of a call, is provided. The mobile station informs presence or absence of own agent for application to be used...http://www.google.com/patents/US6708030?utm_source=gb-gplus-sharePatent US6708030 - Selection method of a handoff system in a CDMA mobile communication systemAdvanced Patent SearchPublication numberUS6708030 B1Publication typeGrantApplication numberUS 09/369,021Publication dateMar 16, 2004Filing dateAug 6, 1999Priority dateAug 14, 1998Fee statusPaidAlso published asCN1129335C, CN1250329A, DE69916945D1, DE69916945T2, EP0981254A2, EP0981254A3, EP0981254B1Publication number09369021, 369021, US 6708030 B1, US 6708030B1, US-B1-6708030, US6708030 B1, US6708030B1InventorsKiyotaka HorikawaOriginal AssigneeNec CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (12), Referenced by (17), Classifications (12), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetSelection method of a handoff system in a CDMA mobile communication systemUS 6708030 B1Abstract A selection method of a handoff system in a CDMA radio data communication system, which is capable of selecting one of a hard handoff system and a soft handoff system depending on situations of a call, is provided. The mobile station informs presence or absence of own agent for application to be used in the communication to a radio base station control equipment when sending a call connection request signal. The radio base station control equipment recognizes the kind of the agent in the mobile station and confirms if a corresponding agent is provided in an agent server. The mobile station determines a handoff system depending on a condition that the agent can be used in the communication or not. The hard handoff system is selected when the agent can be used, and the soft handoff is selected when the agent cannot be used.
As described above, according to the mobile communication system of the CDMA system, even when the mobile station moves between the cells, the mobile station can always communicate with at least one radio base station with no momentary interruption. Therefrom, the mobile communication system of the CDMA system is provided with an advantage in which not only voice communication but also data communication can be carried out. In this specification, a mobile radio system of a CDMA system capable of dealing with also data communication is referred to as �CDMA radio data communication system�.
An explanation will be given of operation of a CDMA system in a hard handoff control in reference to FIG. 10. Here, an explanation will be given of the operation when a mobile station is switched from a state of carrying out data communication with an radio base station (hereinafter, referred to as �old radio base station�) to data communication with other radio base station (hereinafter, referred to as �new radio base station�).
In response to the handoff message, the mobile station returns a handoff message response signal to the base station control equipment via the old radio base station. Thereby, �soft handoff state�, surrounded by a quadrangle of dotted lines in FIG. 11, is brought about. The mobile station carries out data communication with both of the old radio base station and the new radio base station and the old radio base station and the new radio base station carry out data communication with base station control equipment. In other words, the soft handoff state is a state in which communication is carried out by two channels.
In the meantime, there has been proposed a radio data communication system carrying out communication by using an agent which is not a CDMA radio data communication system. In this case, �agent� is referred to a concept which has been proposed as a man/machine interface of next generation in which all of operation necessary for executing a specific instruction is self-controllably executed on the side of a machine with no intermediary of manual operation. In other words, �agent� is referred to a software module capable of spontaneously determining and carrying out what is to be processed.
Further, an agent used in a mobile communication system is referred to as �mobile agent�. That is, the �mobile agent� is an agent for resolving a problem particular to a mobile communication environment. Further, almost all of agents used in the invention correspond to, (or are used by) communication application for eliminating wasteful communication such as data retransmission or the like by call disconnection caused in communication. Caution is required here that in each application, there is existed one agent in correspondence therewith (or used thereby).
For example, JP-A-9-231149 (hereinafter, referred to as prior art 1) has proposed a �radio data communication system� resolving a problem in which the transmission efficiency is significantly deteriorated by retransmission or the like when channel quality is poor by a deterioration in a radio channel state or the like in the case of communication with no intermediary of an agent. According to the radio data communication system described in prior art 1, a first computer connected operationally to a first radio device and a second computer connected operationally to a second radio device communicate data via a radio channel. The respective computers are provided with interfaces of the radio devices to the computers between the first computer and the first radio device and between the second computer and the second radio device, the radio devices are provided with interface functions of the computers to the radio devices and there are arranged a first and a second agent operable self-controllably in accordance with a given situation.
Further, JP-A-9-214516 (hereinafter, referred to as prior art 2) is described with a �mobile terminal� capable of moving in a sub network where a current agent is not present so far as a home agent is present. The mobile terminal described in prior art 2 is provided with a location registering function, a location controlling function and a packet conversion function. According to the location registering function, the terminal is moved and connected to a different sub network and information of self location is informed to a home agent to thereby carry out a registering procedure and is periodically informed to a connected sub network. Further, the location controlling function controls the location information informed from a mobile terminal connected to the same sub network. Further, the packet conversion function detects whether a transmitted party is a mobile terminal or a fixed terminal and converts a packet in a pertinent style. The mobile terminal can move to a sub network where an agent is not present by controlling information necessary for movement of its own.
For example, according to JP-A-9-312869 (referred to as prior art 3), there is disclosed �a method and a base station device as well as a mobile station device for executing �soft hand over start/finish processing� capable of optimizing a radio section capacity in both channels of a reverse channel and a forward channel. That is, according to prior art 3, when soft hand over for switching communication for a while from a first base station currently communicating to a second base station is carried out in accordance with movement of the mobile station, a trigger of start/finish of soft hand over in respect of a reverse communication channel from a mobile station to the base station and a trigger of start/finish of soft hand over in respect of a forward communication channel from the base station to the mobile station, are constituted by triggers which are set independently from each other.
Further, according to JP-A-10-13907 (hereinafter, referred to as prior art 4) there is disclosed �a method of determining a kind of hand over in a CDMA mobile communication system and the CDMA mobile communication system� capable of determining a kind of an optimum hand over from a plurality of kinds of hand over. That is, according to prior art 4, the mobile station determines a start condition of a kind having the most moderate start condition in hand over of a plurality of kinds and when the determination is satisfied, the mobile station informs this to a base station. Further, the mobile station determines a start condition of hand over of a kind having the most moderate start condition other than hand over of specific kinds which cannot be executed and when the determination is satisfied, the mobile station informs this to the base station.
Further, according to JP-A-10-4580 (hereinafter, referred to as prior art 5) although not a mobile communication system of a CDMA system, there is disclosed �a handoff communication system� capable of providing voice quality to a degree of that of conventional soft handoff even hard handoff having a simple system constitution is adopted. That is, according to prior art 5, a base station is installed with voiceless section detecting means for detecting a voiceless section of the communication, voiceless code data generating means for generating voiceless code data by detecting the voiceless section and transmitting data selecting means for selecting the voiceless code data in place of voice data at a front section of the voiceless section and supplying it to a transmitter. In the meantime, a mobile station is installed with handoff condition alleviating means for alleviating a handoff condition by lowering a threshold value of power of a reception signal necessary for switching the base station based on the voiceless code data transmitted from the base station.
SUMMARY OF THE INVENTION The present invention adopts the following technical constitution in order to achieve the above-described object. That is, according to the present invention, a selection method of a handoff system in a CDMA radio data communication system characterized in a selection method of either of a hard handoff system and a soft handoff system as the handoff system, the method comprises: selecting the hard handoff system when the data communication is performed by using an agent function; and selecting the soft handoff system when an agent function is not available for the data communication.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a constitution of a CDMA radio data system to which a selection method of a handoff system according to an embodiment of the present invention is applied.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A detailed explanation will be given of embodiments according to the present invention in reference to the drawings as follows.
In this case, an agent incorporated to the agent server 20 is referred to as a �server side agent�. Further, an agent incorporated by the mobile station 50 is referred to as a �client side agent�.
That is, in requesting call connection, the mobile station 50 transmits a call connection request signal and in the call connection request signal, there is information of presence or absence of an agent and a kind of an agent for application to be used used. In the following, a call connection request signal including information indicating presence of an agent is described as �a call connection request (with agent)� and a call connection request signal including information indicating absence of an agent is described as �a call connection request (without agent)�. Further, in data transmission, the mobile station 50 transmits an agent request signal and in the agent request signal, there is information showing a kind of an agent for application to be used used.
Although according to the above-described embodiments, an explanation has been given of operation when the mobile station 50 makes �a call�, the present invention is similarly applicable to a case in which the mobile station 50 carries out �data transmission� as explained below.
Incidentally, the present invention is not limited to the above-described embodiments but can naturally be modified variously within a range not deviated from the gist of the present invention. For example, according to the above-described embodiments, an explanation has been given only in respect of a case in which the mobile station 50 makes �a call� and a case in which the mobile station 50 carries out �data transmission�, the present invention is applicable also to a case in which the mobile station 50 receives �a call� or a case in which the mobile station 50 carries out �data reception�.
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