CN1123268C - Method and apparatus for performing idle handoff in a multiple access communication system - Google Patents
Method and apparatus for performing idle handoff in a multiple access communication system Download PDFInfo
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- CN1123268C CN1123268C CN98810032A CN98810032A CN1123268C CN 1123268 C CN1123268 C CN 1123268C CN 98810032 A CN98810032 A CN 98810032A CN 98810032 A CN98810032 A CN 98810032A CN 1123268 C CN1123268 C CN 1123268C
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0055—Transmission or use of information for re-establishing the radio link
- H04W36/0061—Transmission or use of information for re-establishing the radio link of neighbour cell information
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/08—Reselecting an access point
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/16—Performing reselection for specific purposes
- H04W36/18—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W48/00—Access restriction; Network selection; Access point selection
- H04W48/20—Selecting an access point
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
- H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W48/00—Access restriction; Network selection; Access point selection
- H04W48/08—Access restriction or access information delivery, e.g. discovery data delivery
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W60/00—Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/04—Wireless resource allocation
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Abstract
In a mobile communication system (14) having a first communication device (2) for communicating with a plurality of second communication devices, a method for performing handoff within the mobile communication system (14) includes transmitting from at least one of the second communication devices to the first communication device (2) a handoff list (60) of second communication devices to which the first communication device is permitted to handoff. A channel assignment message is transmitted from each of the second communications devices in the handoff list (60). The handoff list (60) includes base stations (26 a-o) controlled by a single controller (32) that determines which of the second communication devices transmits the channel assignment message. The base stations (26 a-o) on the handoff list (60) have pilot signals and the energy levels of the pilot signals are measured by the first communication device. The measured energy levels are transmitted to the controller (32) and compared by the controller (32) to provide an energy level list of base stations (26 a-o) according to the comparing. The energy level list is transmitted to the first communication device and the handoff is performed according to the energy level list.
Description
Invention field
The present invention relates to communication system.Specifically, the present invention relates to be used for carry out idle novel method and the device that switches at multi-address communication system.In addition, the present invention relates to be used for distributing the novel method of traffic channel at multi-address communication system.The invention still further relates to the method for the required amount of switched that is used for reducing at the queuing mobile radio station and takes place when waiting for traffic channel at multi-address communication system.
Description of related art
Generally speaking, communication system is forbidden being under system's Access status at mobile radio station and is switched.System's Access status is by sending on the access channel or starting the state of communicating by letter by the base station by sending on paging channel by mobile radio station.In example embodiment, send message according to code division multiple access (CDMA) communication format, this is at United States Patent (USP) the 4th, 901, describe in detail in No. 307 (denomination of invention is " the spread spectrum multiple access communication system at utilization satellite or terrestrial repetition station ") and the United States Patent (USP) the 5th, 103,459 (denomination of invention is " being used for producing in cdma cellular shape telephone system the system and method for waveform "), wherein above-mentioned two patents have transferred assignee of the present invention, and are incorporated herein as the reference data.In the prior art, known to the paging of calling out startup and the utilization of access channel, and this describes in detail at interim (interim) the standard I S-95-A (denomination of invention is " mobile radio station-base station compatibility standard that is used for double mode broadband spread-spectrum cellular communication system ") of TIA/EIA.A feature of cdma system is to reuse same frequency in each sub-district.Diversity combination is to receive the signal of the receiver of the signal that carries identical information combination by different propagated to provide for the improvement estimation approach that sends signal.At United States Patent (USP) 5,109, but the receiver of describing the advantage that is used to utilize the diversity signal that carries identical information send by different propagation paths operations or by different transmitters in No. 390 (denomination of invention is " diversity receiver in cdma cellular shape telephone system ") designs, above-mentioned patent has transferred assignee of the present invention, and is incorporated herein as the reference data.
Soft handover is to be used for moving on to from a sub-district mobile radio station of another sub-district in the method for boundary (as long as this mobile radio station is positioned at this boundary vicinity) reception from the information of the base station of the two or more sub-districts of service.By above-mentioned diversity combining method, the signal that combination is sent by the base station in the receiver of mobile radio station.At United States Patent (USP) the 5th, 101, No. 501 (denomination of invention is " being used for providing in cdma cellular shape telephone system the method and system of the soft handover in the communication ") and United States Patent (USP) the 5th, 267, disclosed the method and system that is used for providing soft handover in No. 261 (denomination of invention is " the mobile radio station assist in soft handover in cdma cellular shape communication system ") at cdma communication system, wherein a plurality of base stations just communicate with mobile radio station near cell boarder or its, wherein above-mentioned two patents have transferred assignee of the present invention, and are incorporated herein as the reference data.Direct-cut operation and soft handover do not coexist and pick up (pick up) before by the sub-district that enters, by the mobile radio station of the cell lost that to be ready leaving from a sub-district to another sub-district.
Cause high cdma system capacity for the utilization of the same frequency in each sub-district and the utilization of soft handover.The repeated use of the same frequency in adjacent cell causes the faster variation near the forward link signal to noise ratio of cell boarder.This is because the sub-district that received by mobile radio station may decline (fade), and adjacent cell can gain in strength (anti-fading).Generally, when mobile radio station receives two sub-districts, provide every expansion chip by following equation (1) and receive traffic channel energy and ratio for total expanded noise density of the signal that sends by sub-district 1:
In addition, following equation (2) the reception traffic channel energy that provides every expansion chip is to the ratio of total expanded noise density of the signal that sent by sub-district 2:
Wherein, in equation (1) and (2),
I
OcBe total thermal noise,
E
c/ I
Or1, E
c/ I
Or2Be respectively from the sub-district 1 and the fractional part of the traffic channel power that sends of sub-district 2 and
Or1,
Or2It is respectively the fractional part that receives at the mobile radio station place from the traffic channel power of sub-district 1 and sub-district 2.
Consider with respect to
Or1,
Or2, I
OcVery little.When sub-district 1 declines with respect to sub-district 2,
Or1With respect to
Or2Become little, so ratio
Or2/
Or1Become big.So, E
c/ I
O1Diminish.If mobile radio station is not in soft changing state, this variation of signal to noise ratio may cause problem so.Yet, if mobile radio station is in the soft changing state that is in adjacent cell, so since mobile radio station to carrying out the diversity combination, so the variation of signal to noise ratio is not a problem from the forward traffic channel of two sub-districts.Though by E
c/ I
O1First path that provides diminishes, but by E
c/ I
O2It is big that second path that provides becomes.So the decline of a sub-district increases the signal to noise ratio of other sub-districts.
Paging is the method that information is sent to mobile radio station, and it points out to start mobile-terminated (terminated) business or the order mobile radio station receives new Overhead.At United States Patent (USP) the 5th, 392, No. 387 (denomination of invention is " be used for reduce in the power consumption of mobile communication receiver apparatus and method ") and pending U.S. Patent Application the 08/206th, No. 701 (applications on March 7th, 1994, it is a United States Patent (USP) the 5th, 392, No. 287 renewal application) the middle method that is used to start base station initiated calling of describing, wherein above-mentioned two patents and patent application have transferred assignee of the present invention, and are incorporated herein as the reference data.The present invention also can be used for mobile radio station and start to call out, and its method is described in No. the 08/219th, 867, pending U.S. Patent Application (application on January 18th, 1996, transferred assignee of the present invention and be incorporated herein as the reference data).
In time slot (slotted) paging system, mobile radio station monitoring paging channel in short predetermined time interval, and do not monitor paging channel once more until next predetermined time interval.In IS-95-A, the method for monitoring paging channel periodically is called slotted mode, and mobile radio station can be monitored paging channel in 80 milliseconds in per 1.28 seconds.The user can be as required, makes during between the monitoring at interval longer.Before can each preassigned time slot of paging mobile station, mobile radio station wakes (becoming existing) up, and again synchronously or improve it in the base station synchronously.So, paging or other message of mobile radio station monitoring in time slot.After the interval, it is not existing that mobile radio station can become, and do not monitor paging channel, before distributing time slot at the next one.Before mobile radio station and the existing propagation traffic information of mobile communication system and after the mobile radio station acquisition and the timing of communication system are synchronous, mobile radio station is in idle condition.In idle condition, mobile radio station can receive message, reception incoming call, start and call out, start registration or initiation message transmission.When under the mobile radio station idle condition, IS-95-A allow mobile radio station except the interval that requires its distribution time slot of mobile radio station monitoring whenever execution is idle switches.
Yet when mobile radio station originating call or paging receiving, it enters system's Access status and sends originating information or page-response message.When being in system's Access status, the IS-95-A mobile radio station is not operated under slotted mode.This is so-called non-time slot operations.Specifically, mobile radio station continuous monitoring paging channel until pointed to the different conditions or the situation that makes a mistake by the base station, allows the mobile radio station Access status that logs off.About operation and the originating information of starting, describe example embodiment, but its principle is directly used in mobile terminating call treatment and page-response message.After mobile radio station sends originating information and confirmation of receipt, the mobile stations wait channel assignment message, its indication should be carried out the traffic communication from the base station to the mobile radio station on which channel.
In case receive channel assignment messages, mobile radio station are got back to the traffic channel of distribution, in reception information on the forward traffic channel and begin to send on the reverse traffic channel.Forward traffic channel is the channel that information is sent to mobile radio station thereon from the base station, and the reverse traffic channel is the traffic channel that information is sent to the base station thereon from mobile radio station.
The interval that sends between the time of originating information and time that mobile radio station is accepted channel assignment message at mobile radio station depends on the supplier who carries out each infrastructure.Its scope can be from being less than 1/2 second to several seconds.Mobile radio station all is in system's Access status, until mobile radio station receive channel assignment messages.
Paging channel is not generally supported soft handover.So, foregoing fading problem takes place.Generally, be higher than traffic channel, resist these phenomenons, start and the termination of a plurality of traffic channels, so make the capacity loss minimum by this more high power because paging channel can be handled to call out by the transmitting power that makes paging channel.In order to be supported in the soft handover on the paging channel, send identical information on the paging channel of system in all sub-districts, so dynamically reduce the capacity of whole paging channel.
Though be in idle condition, allow mobile radio station to carry out and switch.Be typically, no matter when from the paging receiving level of a sub-district apparently higher than another sub-district, mobile radio station is all carried out switching.Generally, before mobile radio station begins to monitor time slot, carry out this free time switching.Yet, there is such situation, that is, mobile radio station can not be selected correct sub-district before time slot begins, and mobile radio station must continue to monitor existing sub-district.Though under system's Access status, do not allow mobile radio station to carry out idle the switching.
Yet, when mobile radio station is in system's Access status, there is such situation, that is, and signal to noise ratio E
c/ I
O1Variation so fast so that message error rate is very high, and mobile radio station can not correctly be received in the signaling message that sends on the paging channel.As a result, mobile radio station can not the receive channel assignment messages.This cause call out start unsuccessful.If it did not receive any paging channel message in one second, IS-95-A allows the mobile radio station Access status that logs off so, gets back to the mobile radio station idle condition.So mobile radio station is the receive channel assignment messages not, and calling is started unsuccessful.
When at first mobile radio station being distributed to traffic channel, there is similar problem.IS-95-A only allows single base station is distributed to mobile radio station.If another sub-district is powerful or becomes more powerful that mobile radio station can not successfully receive forward traffic channel so.As a result, lost-call.Problem is that mobile radio station is distributed to the traffic channel with single existing group membership, and is not under the soft changing state.
Under IS-95-A, enter soft changing state in order to make mobile radio station, the following step must take place.At first, mobile radio station must determine whether the pilot tone of another base station is higher than the predetermined power threshold value.Secondly, mobile radio station must send Pilot Strength Measurement Message.The 3rd, infrastructure must be set up switching, and hand off direction message (handoff direction message) is sent to mobile radio station.According to environment and implementation status, this time that may need the hundreds of millisecond is to the time that substantially exceeds 1 second.
So,,, do not support soft handover when mobile radio station is under system's Access status though generally in the IS-95-A system, support soft handover.Therefore, need system to allow soft handover, mobile radio station is in system's Access status simultaneously, is provided at increase reliability and other favourable parts in system's access process.
Summary of the invention
In mobile communication system with first communicator that communicates with a plurality of second communication devices, be used for comprising at least one from the second communication device of second communication device switching table sent to first communicator, wherein allow facility first communicator to switch to the second communication device in the method that mobile communication system carry out to be switched.Each second communication device channel assignment message from switching table.Switching table comprises which second communication device channel assignment message wherein above-mentioned controller determines by the base station of single controller control.
Base station on switching table has pilot signal, and by the energy level of the first communicator measurement pilot signals.To record energy level and send to controller, and they come to provide according to comparative result the energy level table of base station by the controller comparator.The energy level table is sent to first communicator, and carry out switching according to the energy level table.
The present invention also describes other improvement of the operation that can improve on paging and access channel.The present invention's permission is under system's Access status at mobile radio station switches.This allows mobile radio station to receive the very high base station of its signal to noise ratio, thereby message error rate is very low.This is avoided because can not the paging receiving channel, and lost-call is set up.
Another characteristic of the present invention is that it allows infrastructure to determine which base station should send to mobile radio station with assignment messages.This has guaranteed that mobile radio station can switch to different base station, and has the traffic channel on new base station of distributing to it, does not postpone.
Another characteristic of the present invention is that it allowed before mobile radio station is distributed to traffic channel, and infrastructure determines which base station should be in existing group of mobile radio station.Existing group is the group of base stations of peak signal being distributed to mobile radio station.This allows infrastructure to determine whether to exist enough resources that mobile radio station is arranged under the soft changing state before mobile radio station is distributed to traffic channel.Because near the mobile radio station that is positioned at the cell boarder can be arranged under the soft changing state after being assigned to traffic channel in request immediately, so this is of great use.In addition, this makes the call lose minimum that quick variation owing to the top signal to noise ratio of mentioning causes.
At last, the characteristic that proposes above provides the special utilization of priority visit and channel allocation (PACA) operation, and it allows the user according to the limited communication resource of formulating of owner priority visit.Though describe the present invention according to cdma system, the present invention can be used for any cellular or satellite communication system.
Description of drawings
In conjunction with the accompanying drawings, from following detailed, characteristic of the present invention, purpose and advantage will be apparent, and wherein same numeral is done corresponding expression in the accompanying drawings:
Fig. 1 be comprise with group of base stations in the block diagram of communication system of the present invention of the mobile radio station that communicates of a base station;
Fig. 2 illustrates and the corresponding cell layout in the base station of Fig. 1;
Fig. 3 A-D illustrates the base station table that sends to the mobile radio station in the communication system of Fig. 1; With
Fig. 4 is illustrated in the pilot tone E of the mobile radio station that moves between two base stations
c/ I
o
The detailed description of preferred embodiment
Referring now to Fig. 1, communication system 14 is shown.Communication system 14 comprises mobile radio station 2, and it has processor controls 18 and base station 26a-o.In example embodiment, base station 26a is corresponding respectively at the sub-district 36a among Fig. 2.So for example, base station 26a provides the covering to sub-district 36a.Enter system at the back mobile radio station 2 that powers on and determine sub-state.System determines that processor (not shown) select to carry out the system that attempts and required frequency information is provided to receiver 8 that catches.Though illustrate respectively, can in processor controls 18, executive system determine processor.Carry out processor controls 18 under can the program control in being stored in memory in microprocessor operating or the microcontroller.
In example embodiment, mobile radio station 2 moves into the sub-states of pilot capture (substate), wherein attempts catching the parameter demodulated pilot signal according to what determine in system to receive in the sub-state, to catch the CDMA pilot signal according to catching parameter.In antenna 4 place's received signals (if present), and pass through duplexer 6 to receiver 8.Receiver 8 down-conversions, amplify received signal, analog signal conversion is become numeral expression and signal is delivered to searcher 10.Searcher 10 is attempted by test pseudo noise (PN) biasing, acquisition pilot signal.By coming restituted signal according to the signal energy of PN biasing hypothesis and mensuration restituted signal, test PN biasing.Known designs and the implement searcher hardware of catching in the prior art for CDMA, and in No. the 5th, 109,390, above-mentioned United States Patent (USP), describe in detail.
When searcher 10 detects when having the pilot signal that energy is higher than predetermined threshold, mobile radio station 2 enters the sub-state of synchronization channel acquisition, and attempts catching synchronizing channel.Generally, comprise fundamental system information,, but the most important thing is to provide timing information to mobile radio station 2 such as system banner (SID) and network identity (NID) as the synchronizing channel of propagating by the base station.Mobile radio station 2 is regulated its timing according to synchronizing information, and enters the mobile radio station idle condition.
In case successfully catch synchronizing channel, mobile radio station 2 beginnings are according to predetermined paging form monitoring paging channel.Mobile radio station 2 is according to the predetermined walsh sequence restituted signal that is preserved for the paging channel transmission.For example, if send the acquisition pilot signal by base station 26a, mobile radio station 2 is according to timing information that is provided by synchronizing channel and the predetermined Walsh page monitoring paging channel of utilization so.Base station 26a sends Overhead off and on paging channel.
Referring now to Fig. 3 A-D, the base station table 50,60,70,80 that sends to mobile radio station 2 is shown, in communication system 9 of the present invention, to allow idle the switching.In IS-95-A, provide contiguous table 50 to mobile radio station 2 by the base station 26a-n in contiguous table message.Here, also will be close to table 50 and be called NGHBR_LIST_BASE50.NGHBR_LIST_BASE50 is near the base station 26b-k table the geography of base station 26a, and it can provide strong signal to mobile radio station 2, and is called the candidate of the free time switching of mobile radio station 2.
Base station controller 32 is responsible for providing information between the 26a-o of base station, in order to providing information from main telephone exchange (not shown) to base station 26a-o selectively, and provides the inner message that produces to base station 26a-o.It should be noted that the present invention is used in the situation that some interior base stations of contiguous table 50 are not subjected to the control of same base controller 32 equally.
If after receiving Overhead, send the pilot signal of catching by base station 26a by mobile radio station 2, mobile radio station 2 can number send to base station 26a by the mobile logo with it and register (registerwith) base station 26a so.So after successfully registering base station 26a, mobile radio station 2 enters idle condition, and under the slotted paging pattern its assigned paging channel of monitoring.If do not carry out registration, mobile radio station 2 also enters idle condition and monitoring is sent by base station 26a under the slotted paging pattern its assigned paging channel so.
Under the slotted paging pattern, base station 26a sends any paging or the signaling information that directly arrive mobile radio station 2 in being called the predetermined time interval of time slot.In example embodiment,, determine time slot and paging channel, wherein base station 26a and mobile radio station 2 known its registrations according to the hash function of mobile logo number.
In the present invention, base station 26a wherein allows mobile radio station 2 to carry out idle the switching under system's Access status to the switching table 60 of mobile radio station 2 transmission base stations.Here also switching table 60 is called LIST_BASE60.Base station in LIST_BASE60 generally is the subset of base stations in NGHBR_LIST_BASE50, and generally uses identical base station controller 32.For example, NGHBR_LIST_BASE50 can comprise all base station 26b-k, but LIST_BASE60 can include only base station 26b, 26c, 26g and 26h.
When mobile radio station 2 originating calls, message generator 20 produces originating information and send it on access channel.Can in programming, realize message generator 20 with the microprocessor of carrying out above-mentioned functions.Though illustrate as discrete component, can in processor controls 18, realize message generator 20.Receive originating information, and by the current base station 26a demodulation of monitoring of mobile radio station.In response to the reception originating information, each the base station channel assignment message in LIST_BASE60, it represents the traffic channel of executive communication thereon.Generally, be used for not necessarily being used for and the identical walsh channel that communicates in second base station of LIST_BASE60 with the Walsh channel that communicates in first base station of LIST_BASE60.Because a plurality of base stations channel assignment message, so mobile radio station 2 can be under system's Access status and after originating information being sent to the arbitrary base station that is under system's Access status, carry out idle the switching, and still can the receive channel assignment messages.
In another embodiment, mobile radio station 2 sends to base station 26a to originating information, waits for the affirmation of originating information then.Do not allow mobile radio station 2 to carry out and switch, until mobile radio station 2 confirmations of receipt.Yet after mobile radio station 2 confirmations of receipt, it can carry out the free time switching of the arbitrary base station in LIST_BASE60.
In another embodiment, mobile radio station 2 is used in the process described in the IS-95-A and sends originating information, this is in pending U.S. Patent Application the 08/412nd, No. 648 (denomination of invention is " RACH ", application on March 12nd, 1994, and transferred assignee of the present invention, and be incorporated herein as the reference data) the middle detailed description in detail.If from receive the affirmation from base station 26a in predetermined time-out period, mobile radio station does not increase its transmitted power so, and attempts sending once more message.If mobile radio station 2 can not receive the affirmation from base station 26a after the trial of some, and another base station, for example base station 26b is more powerful, the free time that allows mobile radio station 2 to carry out base station 26b so switches, and restarts to send originating information.
In one embodiment, each the base station channel assignment message in LIST_BASE60, its only expression be used for the traffic channel that oneself communicates with it.In another embodiment, each base station 26a-i in LIST_BASE60 sends the same channel assignment messages, it not only represents traffic channel is used for communicating in certain base station, and also expression is used for this traffic channel and communicates in all base stations of LIST_BASE60.This need can obtain traffic channel by base station controller 32 propagation in the base station in LIST_BASE60.By the channel assignment message from a plurality of base stations is provided, can strengthen the success rate of channel allocation process greatly.
Above-mentioned processing allows infrastructure to set up soft handover, and be included in the channel assignment message more than existing group an of member.Replace at first communicating with a base station, move into soft handover then, mobile radio station 2 can enter soft changing state immediately, and receives the traffic communication from two or more base stations immediately.This has accelerated to make mobile radio station 2 to enter the processing procedure of soft handover, and it has improved the performance of communication system 9, and makes because the call lose minimum that low forward traffic channel signal to noise ratio causes.
In an embodiment of this processing, the soft handover of base station foundation and all base stations in LIST_BASE60.In another embodiment of this processing, the soft handover with subset of base stations in LIST_BASE60 is set up in the base station, and is sent in the information in the required channel assignment message of mobile radio station 2, enters soft handover.This information comprises the homogeneity (identity) of this subset of base stations.In IS-95-A, Pilot PN Offset identification base station.
At antenna 4 places of mobile radio station 2, receive the beep-page message that sends by base station 26a-i.So, provide reception message by duplexer 6 to receiver 8, wherein down-conversion and amplification received signal in receiver 8.Demodulator 12a-j to demodulate reception message provides down-conversion message.According to the information from searcher 10, processor controls 18 is selected the channel of Incoming paging channel or mobile radio station 2 demodulation.In one embodiment, demodulator 12a-j only monitors a base station.
Can determine that from the searcher 10 of cooperating another base station is preferable with processor controls 18.So the demodulator demodulation is from the received signal of another base station.Because mobile radio station 2 receives from the assignment messages more than a base station, so mobile radio station 2 can be carried out idle the switching under system's Access status.In another embodiment, mobile radio station 2 monitoring all base stations in LIST_BASE60, and the signal in LIST_BASE60, discerned of demodulation.
In a preferred embodiment, can not separately provide LIST_BASE60 from the contiguous table 50 the contiguous table message.But, all members' that comprise contiguous table 50 combination (composite) table 70 is provided.Sign 72 is also included within the combination table 70 to represent which member in the contiguous table 50 also is the member of LIST_BASE60.In example embodiment, a retention 72 that is used in the Overhead Message is illustrated in which base station of appointment in the contiguous table message in LIST_BASE60.In IS-95-A, in Overhead Message, provide base station retention 72 to specify which member in the contiguous table 50 in LIST_BASE60.
In example embodiment, the contiguous table of IS-95-A message comprises the Pilot PN Offset that is used in the base station of NGHBR_LIST_BASE50, and is illustrated in which base station in the contiguous table message in LIST_BASE60.Transmission is for the pilot PN sequence of current base station, and coming provides identification other base stations PN the benchmark of biasing to mobile radio station 2.
As mentioned above, require all base stations in LIST_BASE60 that channel assignment message is sent to mobile radio station 2.Though this allows mobile radio station to switch, and increases the success rate of channel allocation process then, it requires additional paging channel capacity to be used for all-calls foundation.
The change of this process is that the base station pilot table that is higher than the predetermined power thresholding is sent to mobile radio station 2 with the influence that reduces the paging channel capacity.This table is LIST_MOBILE80, and it is also referred to as energy meter 80.In one embodiment, searcher 10 demodulated pilot signals, the PN followed by the base station in NGHBR_LIST_BASE50 after the PN of the base station of preference in the LIST_BASE60 biasing simultaneously setovers, then according to residue PN biasing demodulation.The method that is used to provide the optimized search priorization is described in No. 5,267,261, above-mentioned United States Patent (USP).
In example embodiment, searcher 10 is according to the Pilot PN Offset demodulated received signal, and the energy of measurement demodulation pilot frequency.Provide energy value to processor controls 18.Processor controls 18 is compared the energy of restituted signal with threshold value, and compiling energy meter 80.Energy meter 80 comprises the PN bias table that is higher than the energy threshold that is used by processor controls 18.Energy meter 80 can be appointed as LIST_MOBILE80.In case compiled LIST_MOBILE80, on access channel, send it, and receive by the base station 26a that mobile radio station 2 is just being monitored.In example embodiment, LIST_MOBILE80 is included in the originating information.
In another embodiment, by receiving LIST_MOBILE80 more than a base station 26a-o.Provide LIST_MOBILE80 to base station controller 32.In preferred embodiment, send the thresholding that mobile radio station 2 is used for determining whether to be included in the base station among the LIST_MOBILE80 by base station 26a-o, as the Overhead Message part.In preferred embodiment, thresholding can be the T_ADD value that sends in the IS-95-A system parameters message.Currently determined whether on traffic channel the IS-95-A Pilot Strength Measurement Message to be sent to the base station with this T_ADD value by the IS-95-A mobile radio station, its expression mobile radio station has detected the pilot tone above T_ADD.
Referring now to Fig. 4, illustrate when mobile radio station 2 when base station 26a shifts to base station 26b, for by base station 26a, the E of the IS-95-A pilot channel that b propagates
c/ I
oGraphic representation.When mobile radio station 2 was fully in the area of coverage of base station 26a, shown in zone 38, the pilot channel of base station 26b was lower than the T_ADD level.Similarly, complete in the area of coverage of base station 26b when mobile radio station 2, shown in zone 41, the level channel of base station 26a is lower than the T_ADD level.When mobile radio station 2 was in zone 38, it is report base station 26b in originating information not.Similarly, when mobile radio station 2 the zone 41 in, it in originating information the report base station 26a.
When mobile radio station 2 the zone 39 in, for the pilot tone E of base station 26b
c/ I
oBe higher than T_ADD, and mobile radio station is reported base station 26b in originating information.Similarly, when mobile radio station 2 in zone 40, be higher than T_ADD for the pilot tone of base station 26a, and base station 26a is reported in base station 2 in originating information.The E that preferred embodiment will be disclosed in IS-95-A
c/ I
oBe used for these measurements.Yet the another kind that can be used in signal strength signal intensity well known in the prior art or signal to noise ratio is equally measured.
In preferred embodiment, the free time that allows mobile radio station 2 only to carry out the base station in LIST-MOBILE and LIST_BASE60 switches.Group of base stations in above-mentioned table can be appointed as LIST_BOTH.It has two advantages.At first, infrastructure only need be sent in the feasible candidate that is switched for the free time by the conduct of the channel assignment message in those base stations of mobile radio station identification, and allows mobile radio station to switch.This is the group of base stations that provides in LIST_BOTH.It has reduced required additional messages greatly and has sent.Secondly, LIST_MOBILE provides the pilot tone that is higher than T_ADD table to base station controller 32.This allows infrastructure to discern which base station should be as the existing group membership of mobile radio station.So, set up soft handover for base station controller 32 when mobile radio station is distributed to traffic channel, soft handover is set up in the base station that it can only be used among the LIST_MOBILE.
In another embodiment, 2 base stations in LIST_BOTH of mobile radio station send to the base station in its originating information.This has reduced must be from the amount of information of mobile radio station 2 transmissions.In addition, its allows infrastructure to set up soft handover, and in channel assignment message, comprise existing group more than one member.Channel assignment message can be included in the Pilot PN Offset of the base station in existing group, mobile radio station 2 can enter soft changing state immediately, and receive traffic communication immediately from two or more base stations, rather than at first communicate in a base station, enter soft handover then, and this can be because capacity or other restrictions become infeasible.
For example, if mobile radio station 2 be arranged in sub-district 36a near with the position 37 on 36b border, sub-district, the Pilot PN Offset of LIST_MOBILE identification base station 26b so.By base station 26a, the channel assignment message identification that b sends is at base station 26a, and the traffic channel of the communication between b and the mobile radio station 2 is for the usefulness of mobile radio station 2.At least a tuning demodulator 12a-j receives the traffic channel information from base station 26a, and tuning another demodulator 12a-j receives the traffic channel information from base station 26b.A plurality of demodulator 12a-j begin demodulation by base station 26a, the traffic channel signal that b sends.Restituted signal is used for diversity combination 34, and its combined reception signal provides to be estimated the improvement that sends data.
In putting into practice the process of method of the present invention, mobile radio station 2 is not carried out idle the switching, receives until its that the affirmation that sends message or expression are confirmed that the time limit has crossed is overtime.This allows mobile radio station 2 to receive the affirmation that its access channel is inquired after.Also allow the affirmation of 26a generation in base station except the affirmation that is produced by base station controller 32, wherein mobile radio station is inquired after its access channel and is sent to above-mentioned base station 26a.This has reduced delay, and it is faster to make call setup handle.In addition, if mobile radio station 2 is to be in system's Access status and to confirm overtimely to carry out idle switching after expired, mobile radio station 2 must restart access channel and inquires after process of transmitting so.This is identical with the situation that mobile radio station 2 sends new initial message.
In another embodiment, mobile radio station 2 is before confirmation of receipt, and the free time of carrying out the base station in LIST_BASE60 switches.So all base stations in LIST_BASE60 must send affirmation, and base station controller 32 must help to produce to confirm.In the modification process of another embodiment, mobile radio station 2 can be carried out idle switching the in base station in LIST_MOBILE before confirmation of receipt.Similarly, all base stations in LIST_MOBILE must send affirmation, must comprise base station controller 32 then in producing the affirmation process.
In preferred embodiment, the invention provides by base station 26a channel assignment message, but the contingency that mobile radio station 2 does not receive.Base station 26a can receive the originating information from mobile radio station 2, but mobile radio station 2 can not confirmation of receipt receives the channel assignment message from the originating information of base station 26a.Even without receiving the confirmation message, mobile radio station 2 for example also can be carried out the free time of base station 26b and switch.
Base station 26b sends to mobile radio station 2 to channel assignment message, and mobile radio station 2 resends originating information simultaneously.In example embodiment, when sending acknowledge message, follow its indication that also has any bar message to be identified.Mobile radio station 2 has been ignored channel assignment message, unless with the corresponding designator of the originating information of nearest transmission.The present invention includes the several method of this problem of correction.A kind of method is that base station 26b is used in the identical affirmation designator in the originating information that is received by base station 26a.By confirming that indicator value sends to base station 26b from base station 26a, can do like this.In another embodiment, if its receive channel assignment messages, and be tuned to by the channel assignment message channel appointed, mobile radio station 2 can stop to send visit and inquires after so.
In improved embodiment, the paging channel structure of all base stations (base station in LIST_BASE) that permission mobile radio station 2 switches to is identical.Do not support the base station of these abilities to be not included among the LIST_BASE60.
This method also is used for supporting PACA.Known in the prior art this PACA characteristic, and in " description of TIA/EIA/IS-53-A cellular characteristics ", describe in detail.When calling PACA, under the unavailable situation of traffic channel, to obtain in the process of traffic channel, mobile radio station 2 has been endowed the priority that is better than other mobile radio stations.Specifically, mobile radio station sends the originating information that comprises PACA characteristic codes and dialed number.If traffic channel is obtainable immediately, mobile radio station 2 is distributed to traffic channel so.If traffic channel is not obtainable immediately and authorizes mobile radio station 2 utilization PACA, monitors the base station of mobile radio station 2 so the PACA formation is inserted in the request of mobile radio station 2.For example, base station 26a can insert request in the formation.On the other hand, can be by base station controller 32 management PACA formations.Position in formation depends on the priority of PACA request and the time limit (age) of request.When traffic channel is can obtain the time, distributing to traffic channel in the top request of PACA formation.
When the request of mobile radio station 2 is in the PACA formation, the periodic message of the Subscriber Queue state that mobile radio station 2 can reception notification mobile radio station 2.The problem of PACA is that infrastructure need be known mobile radio station 2 current available sub-districts, so that determine whether channel is free.For most systems, this requires mobile radio station 2 when the idle switching of each execution, registers or resend originating information.Because the emergentness of transition between cdma base station, originating information be registered or be resend to mobile radio station 2 can several times, simultaneously by the border between the base station.Consider it is that mobile radio station 2 can enter soft changing state immediately after it is distributed to traffic channel for second of CDMA.Unless available resource comes support call in a plurality of base stations, can not success otherwise distribute.
By above-mentioned modified originating information, mobile radio station 2 points out to be in other base stations in existing group of mobile radio station, and wherein mobile radio station 2 has been monitored the strong waveguide frequency signal from above-mentioned group of base stations.In one embodiment, mobile radio station 2 sends LIST_MOBILE, and LIST_BOTH is determined in the base station.In another embodiment, mobile radio station 2 sends LIST_BOTH.This allows infrastructure to determine to call out in all required base stations at PACA, and whether resource is idle.In order to reduce to send the speed of originating information, the base station in LIST_BOTH is that mobile radio station moves and needn't resend the base station of originating information.When calling this characteristic, infrastructure need all base stations in LIST_BOTH in the transmit queue condition information.If mobile radio station 2 shifts out the area of coverage of the base station in LIST_BOTH, mobile radio station 2 resends originating information so.
The top description of preferred embodiment is provided, makes those skilled in the art that carry out or use the present invention.For those skilled in the art that, be conspicuous to the various modifications of these embodiment, and the General Principle that limits can be used for other embodiment here and need not to carry out creative work.So, the embodiment shown in the present invention is not limited to here, but according to principle that is disclosed here and the corresponding to wide region of novelty.
Claims (15)
1. one kind is used for carrying out the method for switching in mobile communication system, and this mobile communication system has first communicator that communicates with a plurality of second communication devices, it is characterized in that, described method comprises the following steps:
(a) make described first communicator and at least one described second communication device synchronous;
(b) described at least one second communication device sends to described first communicator with second communication device switching table, wherein allows described first communicator to switch to described second communication device in the described switching table;
(c) described first communicator sends originating information and sends to described second communication device; With
(d) in response to originating information, a plurality of described second communication device channel assignment message in the described switching table.
2. the method for claim 1 is characterized in that, the described second communication device of each in described switching table channel assignment message.
3. the method for claim 1 is characterized in that, described switching table comprises the base station that is subjected to single controller control.
4. method as claimed in claim 3 is characterized in that, described controller determines which described second communication device sends described channel assignment message.
5. method as claimed in claim 3 is characterized in that, the described base station in described switching table has pilot signal, and described method also comprises the following steps:
(e) measure the described energy level of described pilot signal by described first communicator;
(f) described mensuration energy level is sent to described controller;
(g) by the more described transmission energy level of described controller; With
(h), provide the energy level table of base station according to described comparative result.
6. method as claimed in claim 5 is characterized in that, comprises the step that described energy level table is sent to described first communicator.
7. method as claimed in claim 6 is characterized in that, comprises according to described energy level table carrying out the step of switching.
8. method as claimed in claim 7 is characterized in that, comprises the step of the switching of only execution and the base station in described switching table and described energy level table.
9. the method for claim 1 is characterized in that, comprises the step that the contiguous table of second communication device is sent to described first communicator, and the second communication device in the wherein said contiguous table is positioned at the geographic vicinity of described first communicator.
10. method as claimed in claim 9 is characterized in that, described switching table and described contiguous table send simultaneously.
11. method as claimed in claim 9 is characterized in that, described contiguous table comprises the base station by a plurality of controller controls.
12. method as claimed in claim 9 is characterized in that, is included in the described second communication device subclass that described vicinity is shown at the described second communication device on the described switching table.
13. the method for claim 1 is characterized in that, step (d) is afterwards followed by carrying out the switching of described first communicator from a described second communication device to another described second communication device.
14. method as claimed in claim 13 is characterized in that, when described first communicator is in idle pulley, the switching of described first communicator takes place.
15. the method for claim 1 is characterized in that, step (d) comprises the channel assignment message of transmission for each base station in described switching table.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US6162697P | 1997-10-09 | 1997-10-09 | |
| US60/061,626 | 1997-10-09 | ||
| US09/168,191 | 1998-10-07 | ||
| US09/168,191 US6178164B1 (en) | 1996-06-07 | 1998-10-07 | Method and apparatus for performing idle handoff in a multiple access communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1280753A CN1280753A (en) | 2001-01-17 |
| CN1123268C true CN1123268C (en) | 2003-10-01 |
Family
ID=26741290
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN98810032A Expired - Lifetime CN1123268C (en) | 1997-10-09 | 1998-10-09 | Method and apparatus for performing idle handoff in a multiple access communication system |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1031250A1 (en) |
| JP (1) | JP4938171B2 (en) |
| KR (1) | KR100573548B1 (en) |
| CN (1) | CN1123268C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013170781A1 (en) * | 2012-05-18 | 2013-11-21 | 电信科学技术研究院 | Method, device, and system for transmitting paging information |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2002353621B2 (en) * | 2001-11-19 | 2004-12-23 | Samsung Electronics Co., Ltd. | Method and apparatus for uplink transmission power control in a CDMA communication system |
| KR100518433B1 (en) * | 2002-10-28 | 2005-09-29 | 엘지전자 주식회사 | System and Method for Processing Hand-over |
| JP2006518127A (en) | 2003-02-18 | 2006-08-03 | ノキア コーポレイション | Picture decoding method |
| CN1751518B (en) | 2003-02-18 | 2010-12-01 | 诺基亚有限公司 | Picture coding method |
| US20050201471A1 (en) | 2004-02-13 | 2005-09-15 | Nokia Corporation | Picture decoding method |
| US9124907B2 (en) | 2004-10-04 | 2015-09-01 | Nokia Technologies Oy | Picture buffering method |
| US7672667B2 (en) * | 2006-01-17 | 2010-03-02 | Telefonaktiebolaget L M Ericsson (Publ) | Broadcast-centric cellular communication system |
| US9326201B2 (en) * | 2006-12-22 | 2016-04-26 | Alcatel Lucent | Detecting and reporting a picocell by a mobile station |
| WO2008154802A1 (en) * | 2007-06-19 | 2008-12-24 | Telefonaktiebolaget L M Ericsson (Publ) | Improved resource reservation during handover in a wireless communication system |
| BRPI0910687A2 (en) * | 2008-04-22 | 2017-12-26 | Nortel Networks Ltd | handover restriction of a mobile station |
-
1998
- 1998-10-09 EP EP98952246A patent/EP1031250A1/en not_active Withdrawn
- 1998-10-09 JP JP2000516502A patent/JP4938171B2/en not_active Expired - Lifetime
- 1998-10-09 KR KR1020007003710A patent/KR100573548B1/en not_active IP Right Cessation
- 1998-10-09 CN CN98810032A patent/CN1123268C/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013170781A1 (en) * | 2012-05-18 | 2013-11-21 | 电信科学技术研究院 | Method, device, and system for transmitting paging information |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2004500723A (en) | 2004-01-08 |
| KR100573548B1 (en) | 2006-04-24 |
| EP1031250A1 (en) | 2000-08-30 |
| KR20010030960A (en) | 2001-04-16 |
| CN1280753A (en) | 2001-01-17 |
| JP4938171B2 (en) | 2012-05-23 |
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