CN1085031C - Mobile assisted handover arrangements for digital cellular telephone networks - Google Patents
Mobile assisted handover arrangements for digital cellular telephone networks Download PDFInfo
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- CN1085031C CN1085031C CN96195681A CN96195681A CN1085031C CN 1085031 C CN1085031 C CN 1085031C CN 96195681 A CN96195681 A CN 96195681A CN 96195681 A CN96195681 A CN 96195681A CN 1085031 C CN1085031 C CN 1085031C
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
- H04W36/302—Reselection being triggered by specific parameters by measured or perceived connection quality data due to low signal strength
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/34—Reselection control
- H04W36/38—Reselection control by fixed network equipment
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Abstract
The present invention provides a digital cellular telephone network providing a mobile phone switching scheme, in which a mobile phone provides signals relevant to the intensity of downlink signals. The signals are from a first base station in communication with the mobile phone, and the down links of other selected base stations in the network. A central controller calculates a carrier-to-interference ratio C/I and determines the switching time of the mobile phone, and which other base station the mobile phone needs to be switched to on the basis of the signals.
Description
The present invention relates to be used for the handover scheme (arrangement) of digital cellular telephone net.
Mobile telephone network is set up well in a lot of geographic areas, makes the less and lighter relatively phone can be general.Small and light depending primarily between phone and fixing communication transmitter and receiver used relatively low power emission.Communication transmitter in the base station and receiver usually main geographically with array format be dispersed in equably network range around, and be connected to and be used to control the central network control station of communicating by letter between all base stations and the mobile phone.In the beginning of each call of each communication, central control station dividing frequency and channel are also selected suitable base station.According to frequent situation, during each is called out central controller provide handover scheme with change or change channel is connected phone with frequency in case with different base station communications.Central controller is also monitored with metered call and is used for user's charging.
Usually, the base station is designed to and can provides the suitable a plurality of zones that transmit and receive by zone or so-called " sub-district " that limit, many hexagonal limits joins.The carrier frequency of being used by sub-district is different with arbitrary frequency of using in a tight adjacent sub-district, but identical with the frequency of far point and that isolated by two other sub-district of network usually a little another sub-district use in network.The cellular type of communication cell can use 7 different carrier frequency collection to form easily like this.Certainly, as is known, if mobile phone moves to another sub-district from a sub-district during a calling, then control station can and be designed to shift or switches mobile phone and makes on suitable different frequency and communicate by letter.
At present this be simply by by reported at any time and the sub-district of telephone communication and the signal strength signal intensity between the neighbor cell relatively come to determine.Surpass just in predetermined amount of signal strength signal intensity of communication cell if the signal strength signal intensity of neighbor cell increases, then central controller will switch to this adjacent sub-district to mobile phone.
In fact such scheme is reliable inadequately, especially is operated in the close coastal region of complete open space for needs, near the difficult landform on mountain range with and/or at the network in densely populated zone with high-rise structures.
In article " Nice, France is at the 243-249 page or leaf of XP000444200 for the handoff technique that is used for third generation mobile system, the CHIA mobile radio meeting of holding in 13-15 day in November, 1991 ", the various general criterions that are used for handover scheme have been discussed.In WO-A-9217953, announced a handover scheme, when switching condition seems very essential, then often measure specific C/I ratio therein.
The purpose of this invention is to provide a kind of network and a kind of mobile phone, they can be operated in the landform of difficulty more satisfactorily and also can provide better service in not too difficult landform, even when using density high.
According to an aspect of the present invention, the handover scheme of the digital cellular telephone networks that is used to have a central controller and a plurality of mobile phones is provided, wherein each mobile phone is designed to come the measurement result of the downlink signal strength of the signal strength signal intensity of the down link of measure and transmit first base station on the control channel of network and other base station, and wherein all these signals all are passed to central controller, it determine C/I ratio and no matter when this ratio descend and be lower than predetermined value, then start the switching of mobile phone from first base station to another base station, here, C equals the intensity of down link signal of first base station and the summation of the downlink signal strength that I is other base station.
Have only the C/I ratio when other base station to be higher than predetermined value, controller just preferably starts the switching of the mobile phone from first base station to another base station.
The downlink strength of base station can be preferably before the addition by with network before calculating or coefficient or the regulatory factor of measuring relevant selection revise.
According to a further aspect in the invention, a kind of mobile phone of the digital cellular telephone networks that is used to have handover scheme defined above is provided, the device that comprises the downlink signal strength that is used for periodically measuring the intensity of the down link signal that receives from first base station continuously and on control channel, receives, and the device that is used for these measurement results are sent to first base station from a plurality of other base stations.
Measurement mechanism can be designed to measure the intensity from the down link signal of the peripheral base station that is operated in same carrier.Measurement mechanism also can be designed to measure the intensity from the down link signal of the immediate peripheral base station that is operated in different carrier frequency.
Describe by way of example according to of the present invention referring now to appended schematic diagram and to be used for digital cellular telephone networks and at the handover scheme of the phone of these networks, wherein:
Fig. 1 is the Utopian plan schematic view of a cellular network;
Fig. 2 is another Utopian plan schematic view of a cellular network;
Fig. 3 is the plan schematic view of the part of a typical cellular network;
Fig. 4 is the end view of the diagrammatic of another cellular network;
Fig. 5 is a Utopian plan schematic view that has with the cellular network of more super sub-districts of reusing carrier frequency; And
Fig. 6 is the glossary of a Fig. 1 to Fig. 5.
The digital cellular mobile telephone network be known and typically each sub-district be designed to send with 3 different carrier frequency, each carrier frequency provides 8 channels (time-multiplexed).Two channels of a carrier frequency are used to control signal, and remaining channel of a carrier frequency and all channels of other two carrier frequency all are used to voice or data send, promptly so-called " business ".Channel is designed in pairs and a channel of every centering is used to send to a mobile phone (down link signal), and this is used to send (uplink signal) from mobile phone to the one other channel in the channel.
Mobile phone at first is connected to usually to make with it with its hithermost sub-district and communicates by letter, and is distributed a pair of channel that is used for service communication by centralized network controller.This is by finishing according to known being exchanged messages on control channel by the program of fine practice.In specific embodiments of the present invention, each mobile phone be designed periodically to respond from other sub-district the signal that comes and by the sub-district Radio Link with the signal strength signal intensity of the signal (down link signal) that below the mode relaying that is described received from other sub-district to central controller.Receiving and measure the purpose of various downlink signal strength, comprise its down link signal, is to be used for the information of specific mobile phone " switching " to another sub-district in order to provide central controller to make.This can guarantee to keep satisfied communication quality when condition changes, normally neighbor cell maybe may enter at present and the part of the sub-district of mobile phone communications receives relatively poor zone because mobile phone more shifts near in this variation.
At Fig. 1, the control channel frequency is reused every 7 sub-districts (C1 is to C7) in cellular network.Normal Traffic Channel frequency is reused every 4 sub-districts (V1 is to V4).In Fig. 1, what be used for Traffic Channel reuses the reuse rank of rank far above control channel, but will notice that " possible interference source " makes control channel use different frequencies." possible interference source " is used to be identified in the system sub-district or the base station of using the same traffic channel frequency set, like this from the signal that may interference source comes may be enough by force with cause present just with the sub-district of mobile phone communications or the interference the base station area.
During the carrying out of a calling, mobile phone is just periodically measured the intensity of down link signal that may interference sources at serving base station and those.All measurement results are reported to central controller, and it calculates the C/I ratio of the Radio Link that is using according to following method:
L
s=just in the intensity of the down link signal of serving base station
L
Is1The intensity of the down link signal of=the first possibility interference source
L
Is2The intensity of the down link signal of=the second possibility interference source ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
L
IsmThe intensity of the down link signal of=the m possibility interference source
The C/I ratio of the Radio Link that is using is calculated as:
C/I＝L
s/(L
is1+L
is2+...+L
ism)
Be lower than predetermined rank when C/I ratio drops to, central controller will switch to another sub-district to mobile phone.This class is measured and is referred to as " directly C/I ratio is measured " sometimes.
In Fig. 2, the rank of Traffic Channel frequency reuse is identical with the rank of control channel frequency reuse.In the drawings, identical Traffic Channel and control channel are reused every 7 sub-districts.
When using network in Fig. 2, during the carrying out of a calling, mobile phone is just periodically measured the intensity at the down link signal of serving base station and those " reference " base stations." reference " base station is used to be identified in a series of adjacent base station on the different control channel frequencies and is selected to be used for estimating the signal level of possibility interference source especially.All these measurement results are reported to central controller, and it calculates the approximate C/I ratio of the Radio Link that is using according to following method:
L
IskThe intensity of the down link signal of=the k possibility interference source (wanting estimated)
L
s=just in the intensity of the down link signal of serving base station
L
Rk1=for k may interference source the intensity of down link signal of first reference base station
L
Rk2=for k may interference source the intensity of down link signal of second reference base station ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ..
L
Rkx=for k may interference source the intensity of down link signal of x reference base station
The interference level of k possibility interference source is approximately:
L
isk＝MAX[(L
rk1 *a
1)，(L
rk2 *a
2)，...，(L
rkx *a
x)]
Here, a
1, a
2..., a
xBe coefficient or the regulatory factor of fixing.This regulatory factor is preset by the measurement of doing for network in the past, and the profile that the composite signal that necessary adjusting makes reference base station is provided is roughly identical with the profile of K possibility interference source in the coverage in serving base station just after regulating.This illustrates in Fig. 3.
Therefore the C/I ratio of the Radio Link that is using is calculated as:
C/I＝L
s/(L
is1+L
is2+...+L
ism)
Be lower than a predetermined rank when C/I ratio drops to, switch by the central controller arrangement.This class criterion is referred to as sometimes based on " approximate C/I ratio ".
Some special environment appears for as shown in FIG. 4 certain location or landform.Like this, when the border of crossing the coverage that a quilt plans, may exist a plurality of sub-districts of on signal strength signal intensity, serving relatively to present the adjacent base station of variation.A typical situation has been described in Fig. 4.
Base station A is covered or serves the part road surface on a hill path but depends on the position of antenna by planning, this base station is the cover part ground region also.The road surface is subjected to the influence of the wireless signal next from many other base stations, so have only frequency seldom enough to be assigned to base station A neatly.Must prevent to be caught by base station A, otherwise it will enter obstruction from the business of ground floor.In order to determine that business from where coming, is used as reference from the selected signal that is positioned at more apogean base station B and C.On the mountain, mobile phone is the visual line of sight at base station B and C, so their downlink signal strength is with respect to being high in serving base station just.At ground region, situation is opposite, because stopped by building from base station B and the next signal of C.
Like this, when operation, mobile phone is designed monitor signal strength and this information is passed to central controller, and it will determine the relative position of mobile phone and decision are switched in fact whether necessary in this specific embodiment.
The following processing of signal strength information:
L
s=just in the intensity of the down link signal of serving base station
L
Cs1The intensity of the down link signal of=first selected base station
L
Cs2The intensity of the down link signal of=the second selected base station ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ..
L
CsxThe intensity of the down link signal of=the X selected base station
And if if only:
The positive logic negative logic
L
Cs1-L
s＞d
1L
Cs1-L
s＜d
1Or L
Cs2-L
s＞d
2And L
Cs2-L
s＜d
2... .... ... ... ... ... ... ... ... .. or L
Csx-L
s＞d
xAnd L
Csx-L
s＜d
xThen mobile phone is in the coverage of being planned, wherein d
1, d
2... d
xBe constant, its value according to just serving base station and those within by the planning coverage and outside the predicted or measured signal strength signal intensity of selected base station determine.Switch the condition that those can be referred to as " coverage control " that submits to like this.
Be used for determining that a typical logical program that switches generally is to be automatically performed as follows by central controller:
(a) just between serving base station, setting up a radio traffic channel a mobile phone and one.
(b) according to the information that receives from network, mobile phone is just periodically measured in other the intensity of down link signal of base station of serving BS and those.All measurement results are by just reporting to central controller in serving base station.Measurement result comprises:
For just in serving base station:
L
u-uplink signal strength
L
d-downlink signal strength
Q
u-uplink quality
Q
d-downlink quality
D-mobile phone and the distance between serving base station just
For other base station
C
N1, C
N2..., C
Nk-Base Station Identification
L
N1, L
N2..., L
Nk-downlink signal strength
(c) when receiving new measurement result, central controller is by checking triggering function checks whether be necessary to switch:
T(L
u，L
d，Q
u，Q
d，D，C
n1，C
n2，...，C
nk，L
n1，L
n2，...，L
nk)
If T＞0, switching are necessary, proceed to step (d).Otherwise get back to step (b).
(d) be necessary when determine switching, in the non-serving base stations of the K from measurement report, central controller selects a plurality of base stations as possible switching target by using corresponding examination function:
Q
ni(L
u，L
d，Q
u，Q
d，D，C
n1，C
n2，...，C
nk，L
n1，L
n2，...，L
nk)
Q
NiBe one by parameterized function to determine by C
NiWhether the base station of identification is qualified as a switching target.If Q
Ni＞0, this base station is qualified.
(e) central controller is determined the priority of qualified switching target by using pri function:
P
ni(L
u，L
d，Q
u，Q
d，D，C
n1，C
n2，...，C
nk，L
n1，L
n2，...，L
nk)
P
NiBe one by parameterized function to determine by C
NiThe relative priority level of the switching target of identification.
(f) central controller order travelling carriage switches to the target BS with limit priority.
For specific embodiments according to the present invention and use changeover program with reference to figure 1 described system, central controller is by programing operation as follows:
When a mobile phone and one are just setting up a radio traffic channel between serving base station, just in signal strength measurement report, from K non-serving base stations, pick out all possible interference source at serving BS.
L
Is1=just first of serving base station may interference source the intensity of down link signal.
L
Is2=just second of serving base station may interference source the intensity of down link signal..........................................................................................................................
L
Ism=just m of serving base station may interference source the intensity of down link signal
Just can be calculated as then at the C/I of serving base station ratio:
CI
s＝L
d/(L
is1+L
is2+...+L
ism)
The triggering function T is defined as:
T＝ci_threshold-CI
s
Here ci_threshold is a predetermined minimum acceptable C/I ratio.
T＞0 means that C/I ratio is inferior to minimum acceptable rank, thus switch to another preferably the base station be necessary.
For by C
NjThe possible switching target of identification is picked out relevant possible interference source from K non-serving base station in measurement report.
L
Inj1=by C
NjThe intensity of the down link signal of first possibility interference source of the base station of identification.
L
Inj2=by C
NjThe intensity of the down link signal of second possibility interference source of the base station of identification........................................................................................................................
L
Injm=by C
NjThe intensity of the down link signal of m possibility interference source of the base station of identification.
Then by C
NjThe C/I ratio of the base station of identification can be calculated as:
CI
nj＝L
nj/(L
inj1+L
inj2+...+L
injm)
Relevant examination function is defined as:
Q＝CI
nj-ci_threshold
Q＞0 means that C/I ratio is better than minimum acceptable rank, so that the base station is proved to be is qualified in to become a switching target.
In fact, by C
NjThe pri function of the base station of identification is defined as:
P
nj＝CI
nj
The priority of possible switching target only is determined according to the C/I ratio of correspondence.C/I is than good more and resultant signal quality is good more, and then priority is high more.
Also may recently determine to switch based on approximate C/I, as previous explain with reference to figure 2.This is just to be used to estimate and to carry out in all reference base station of the C/I of serving base station ratio by picking out from K non-serving base station in measurement report.
L
Rs1=just be used to estimate intensity at the down link signal of first reference base station of the C/I of serving base station ratio
L
Rs2=just be used to estimate intensity at the down link signal of second reference base station of the C/I of serving base station ratio ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
L
Rsx=just be used to estimate intensity at the down link signal of x reference base station of the C/I of serving base station ratio
Then in the program of central controller, for just being calculated as at the C/I of serving base station ratio:
CI
s＝L
d/MAX[(L
rs1 *a
s1)，(L
rs2 *a
s2)，...，(L
rsx *a
sx)]
The triggering function T that is used to switch is defined as:
T＝ci_threshold-CI
s
Here ci_threshold is the acceptable C/I ratio of predefined minimum.
T＞0 means that C/I ratio is inferior to minimum acceptable rank, is necessary so switch to another better base station.
Possible switching target is by C
NjIdentification.This is to pick out in the relevant reference base station in K the non-serving base stations in measurement report.
L
Rnj1=be used for estimation by C
NjThe intensity of the down link signal of first reference base station of the C/I ratio of the base station of identification.
L
Rnj2=be used for estimation by C
NjThe intensity of the down link signal of second reference base station of the C/I ratio of the base station of identification...............................................................................................................................
L
Rnjx=be used for estimation by C
NjThe intensity of the down link signal of x reference base station of the C/I ratio of the base station of identification.
Then by C
NjThe C/I ratio of the base station of identification can be calculated as:
CI
nj＝L
nj/MAX[(L
rnj1 *a
nj1)，(L
rnj2 *a
nj2)，...，(L
rnjx *a
njx)]
Relevant examination function is defined as:
Q＝CI
nj-ci_threshold
Q＞0 means that C/I ratio is better than minimum acceptable rank, so that the base station is proved to be is qualified in to become a switching target.In other words, suppose that the C/I ratio that is used for possibility switching target station is higher than a predetermined value, then switches and can be performed.
The pri function of target BS is by C
NjIdentification also is defined as:
P
nj＝CI
nj
The priority of possible switching target only according to the C/I of correspondence than being determined.C/I is than good more and resultant signal quality is good more, and then priority is high more.
Previously mentioned with reference to Fig. 4, may need certain special scheme in relatively more difficult landform or position.In the place of deciding switching according to the position, provide following program:
In measurement report, from K non-serving base stations, pick out the estimation travelling carriage that is useful on and whether be in selecteed in the coverage that the quilt of the base station of using plans and be positioned at more apogean base station.
L
Cs1=be used to estimate whether travelling carriage is in the intensity of the down link signal of first the selecteed base station in the coverage that the quilt of the base station of using plans.
L
Cs2=be used to estimate whether travelling carriage is in the intensity of the down link signal of second selecteed base station in the coverage that the quilt of the base station of using plans.............................................................................................................................
L
Csx=be used to estimate whether travelling carriage is in the intensity of the down link signal of x selecteed base station in the coverage that the quilt of the base station of using plans.
Trigger function T＞0 or switching function and be provided, if:
Positive logic negative logic L
Cs1-L
d＞d
S1L
Cs1-L
d＜d
S1Or L
Cs2-L
d＞d
S2And L
Cs2-L
d＜d
S2... ... .. ... ... ... ... .. ... ... or L
Csx-L
d＞d
SxAnd L
Csx-L
d＜d
Sx
T＞0 means that travelling carriage is in outside the service area that the quilt of the base station of using plans, is necessary so switch to another base station.
Possible switching target is by C
NjRelevant reference base station is selected in identification from the non-serving base stations of K measurement report.
L
Cnj1=be used to estimate whether travelling carriage is in by C
NjThe intensity of the down link signal of first the selected base station within the service area that the quilt of the base station of identification is planned.
L
Cnj2=be used to estimate whether travelling carriage is in by C
NjThe intensity of the down link signal of second selected base station within the service area that the quilt of the base station of identification is planned..............................................................................................................................
L
Cnjx=be used to estimate whether travelling carriage is in by C
NjThe intensity of the down link signal of the selected base station of the x within the service area that the quilt of the base station of identification is planned.
Examine function Q greater than 0, if:
Positive logic negative logic L
Cnj1-L
Nj＞d
Nj1L
Cjn1-L
Nj＜d
Nj1Or L
Cnj2-L
Nj＞d
Nj2And L
Cnj2-L
Nj＜d
Nj2... ... ... .. ... ... ... ... ... .. ... ... ... or L
Cnjx-L
Nj＞d
NjxAnd L
Cnjx-L
Nj＜d
Njx
Q＞0 means that travelling carriage is in by C
NjThe base station of identification within the service area planned, so it is proved to be qualified in to become a switching target.
For precedence function, used as signal strength signal intensity, business load and C/I are than such factor.
Described handover scheme can be applied to-cellular network of lower support.With reference to figure 5, on cellular network has-configuration of lower support, some sub-districts have the super carrier frequency of reusing therein.The work spectrum of network is divided into two groups, i.e. a conventional reuse group and a super reuse group.Conventional frequency reuse is reused on the distance of safety, for example reuses the distance in the pattern in 7 sub-districts, and the mobile phone on the border of the normally the worst sub-district of close wherein C/I ratio is served in plan.As what name hinted, super frequency reuse can be utilized to produce desired dilatation by very dense ground again.
Some common base stations are equipped with two types frequency.The super frequency reuse of distributing to the base station is divided into several groups, and every group has different interference sources.According to the distribution of the interference that each mobile phone ran into, central controller is defined as bearer service and the only group of frequencies of assigning.
The independent Microcell that its antenna height is significantly less than the roof level only can be equipped with super frequency reuse.Connect by setting up suitable switching, at the Microcell of good position, near the business of the ordinary base station more than that can be absorbed in it effectively.By means of such scheme, base station on every side is referred to as " female base station " usually, and Microcell is referred to as " subbase station " simultaneously.
With the frequency choice mechanism of last-routine that the lower support structure is used only based on the signal strength signal intensity of serving BS.A strong signal means that travelling carriage will distribute a super frequency reuse to give a calling near base station and system.Otherwise, use a conventional frequency reuse.This scheme, flat, general work is better equably.But in interference-limited environment, only signal strength signal intensity does not have actual responsive indication to interference.At open area, signal level is higher usually, but disturbs so same.When signal was more weak, mobile phone may be within the building and be shielded interference preferably.
So use the frequency choice mechanism of specific embodiments of the present invention more effective.Improved handover scheme of the present invention can be applied to frequency and select.Process is as follows:
(a) when call setup, central controller distributes a conventional frequency reuse.
(b) during calling is carried out, when signal strength measurement was available, whether central controller had enough clean super frequency reuse available (be included in the correlator base station those) by using examination function inspection according to following criterion:
-directly C/I ratio is measured (Fig. 1)
-approximate C/I ratio (Fig. 2)
-coverage control (Fig. 4)
(c) if find clean super frequency reuse, then central controller according to priority sorts to spendable super frequency reuse according to each idle business channel number.The idle business channel number is many more, and priority is high more.
(d) central controller switches to mobile phone on the super frequency reuse with limit priority.
(e) for super frequency reuse, whether the Radio Link that the frequent monitoring of central controller is being used is necessary to return conventional frequency reuse to check.Handover trigger function based on following criterion can be used:
-directly C/I ratio is measured
-approximate C/I ratio
The control of-coverage
(f) if be necessary by the conventional frequency reuse of returning of handover trigger function indication, then central controller by use based on the examination function of following criterion and pri function just estimate serving base station with and each conventional frequency reuse of those base stations of adjacent area:
-directly C/I ratio is measured
-approximate C/I ratio
The control of-coverage
(g) central controller switches to mobile phone on the conventional frequency with limit priority.
(h) return step (b).
In the scheme that is described, the intensity of the down link signal of control signal is measured and be used to determine switching criterion and the position of mobile phone in Fig. 4.Can see that the intensity of Traffic Channel down link signal also can be by additional or alternatively use.
Can see, in specific embodiments of the present invention, switching criterion is based on C/I ratio and is determined for just in the predetermined value of of serving base station the time when this ratio drops to be lower than, or opposite, the C/I ratio of possible handover-target base station is monitored to discern and to select a suitable base station in these base stations to be used for switching.
Caption
A-is the ground floor of the base station of control channel altogether
B-is the ground floor of the base station of Traffic Channel altogether
C-is total to control channel and is total to the ground floor of the base station of Traffic Channel
The handover-target base station that D-is possible
E-reference base station A
The F-interference base station
Border, G-coverage
H-reference base station B
The signal level isopleth of I-interference base station
The interference area of J-in service area
The isopleth that is conditioned signal level of K-reference base station A and B
Intentional (+ve logic) service area of (ve logic) service area/base station A of the nothing intention of L-base station A
| (L B2-L A1)＞d BOr (L C1-L A1)＞d C |
Intentional (ve logic) service area of the (+ve logic) service area/base station A of the nothing intention of M-base station A
The cell layer R-that N-base station AO-reference base station BP-reference base station CQ-is used for first common channel of conventional frequency reuse be used in female base station super frequency reuse first altogether the cell layer S-of channel be used for first cell layer of channel altogether at subbase station
| (L B2-L A1)＞d BWith (L C2-L A2)＞d C |
Claims (4)
1, be used to have the handover scheme of the digital cellular telephone networks of a central controller and a plurality of mobile phones, it is characterized in that, each mobile phone is designed to measure and to send the measurement result of the downlink signal strength of the intensity of down link signal of first base station and other base station on the control channel of network, and be that all these signals are passed to central controller, it is determined a C/I ratio and no matter when drops to when being lower than a predetermined value when this C/I ratio, then start the switching of mobile phone from first base station to another base station, here C equals the intensity of the down link signal of first base station, and I is the summation of the downlink signal strength of other base station.
2, according to the handover scheme of claim 1, it is characterized in that having only when the C/I of other base station ratio is higher than predetermined value, controller starts the switching of the mobile phone from first base station to another base station.
3, according to the handover scheme of claim 1 or 2, it is characterized in that the base station down link intensity before the addition can by with network before calculating or measure relevant selected coefficient or regulatory factor and revise.
4, according to the handover scheme of claim 1, the mobile phone that it is characterized in that described digital cellular telephone networks have the down link signal that is used for periodically measuring the intensity of the down link signal that receives from first base station continuously and on control channel, receives from a plurality of other base stations intensity device and be used to send the device of these measurement results to first base station.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9510861.9 | 1995-05-30 | ||
| GBGB9510861.9A GB9510861D0 (en) | 1995-05-30 | 1995-05-30 | Handover arrangements for digital cellular telephone networks |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1191660A CN1191660A (en) | 1998-08-26 |
| CN1085031C true CN1085031C (en) | 2002-05-15 |
Family
ID=10775214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN96195681A Expired - Fee Related CN1085031C (en) | 1995-05-30 | 1996-05-30 | Mobile assisted handover arrangements for digital cellular telephone networks |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0829179A1 (en) |
| CN (1) | CN1085031C (en) |
| AU (1) | AU701840B2 (en) |
| GB (1) | GB9510861D0 (en) |
| WO (1) | WO1996038997A1 (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5970407A (en) * | 1996-12-31 | 1999-10-19 | Telefonaktiebolaget L M Ericsson (Publ) | Compensation for mobile assisted handoff measurement inaccuracies |
| FI104682B (en) | 1997-02-18 | 2000-04-14 | Nokia Networks Oy | Handover in a mobile communication system |
| FI104683B (en) | 1997-02-18 | 2000-04-14 | Nokia Networks Oy | Handover in a mobile communication system |
| FR2768586B1 (en) * | 1997-09-12 | 1999-12-03 | Nortel Matra Cellular | PROVISIONAL ESTIMATE OF THE INTERFERENCE SIGNAL RATIO IN A CELLULAR RADIOCOMMUNICATION NETWORK |
| FR2768584B1 (en) * | 1997-09-12 | 1999-12-03 | Nortel Matra Cellular | DEVICE FOR ALLOCATING RESOURCES IN A RADIO COMMUNICATION NETWORK |
| FI106287B (en) | 1997-09-17 | 2000-12-29 | Nokia Mobile Phones Ltd | Improved procedure for changing base station |
| US6259918B1 (en) | 1999-02-26 | 2001-07-10 | Telefonaktiebolaget Lm (Publ) | Preservation of cell borders at hand-off within a smart antenna cellular system |
| ATE379939T1 (en) * | 1999-08-10 | 2007-12-15 | Motorola Inc | METHODS TO REDUCE INTERFERENCE BETWEEN MOBILE PHONES USING DIFFERENT DUPLEX TECHNOLOGY |
| GB2362297B (en) * | 2000-01-07 | 2003-10-15 | Motorola Inc | Method and apparatus for location based consideration for cellular telephone handoff |
| US7142860B2 (en) | 2001-03-30 | 2006-11-28 | Telefonaktiebolaget Lm Ericsson (Publ) | Network/cell/interface selection in mixed networks |
| US7068626B2 (en) * | 2001-08-16 | 2006-06-27 | Interdigital Technology Corporation | Method of using a mobile unit to autonomously determine a serving cell |
| JP4762033B2 (en) * | 2006-04-07 | 2011-08-31 | 株式会社エヌ・ティ・ティ・ドコモ | Measuring apparatus and area quality measuring method |
| CN101466097B (en) * | 2007-12-17 | 2011-03-16 | 中兴通讯股份有限公司 | Method for providing continuous high speed access for mobile terminal |
| CN102083159A (en) * | 2009-11-30 | 2011-06-01 | 中国移动通信集团北京有限公司 | Switching controlling method in mobile communication system and wireless network controller |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4866710A (en) * | 1988-02-22 | 1989-09-12 | Motorola, Inc. | Reuse groups for scan monitoring in digital cellular systems |
| US5042082A (en) * | 1989-06-26 | 1991-08-20 | Telefonaktiebolaget L. M. Ericsson | Mobile assisted handoff |
| WO1992017953A1 (en) * | 1991-04-01 | 1992-10-15 | Motorola, Inc. | Target channel verification in a radiotelephone system |
-
1995
- 1995-05-30 GB GBGB9510861.9A patent/GB9510861D0/en active Pending
-
1996
- 1996-05-30 WO PCT/GB1996/001280 patent/WO1996038997A1/en not_active Application Discontinuation
- 1996-05-30 CN CN96195681A patent/CN1085031C/en not_active Expired - Fee Related
- 1996-05-30 AU AU58290/96A patent/AU701840B2/en not_active Ceased
- 1996-05-30 EP EP96919926A patent/EP0829179A1/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4866710A (en) * | 1988-02-22 | 1989-09-12 | Motorola, Inc. | Reuse groups for scan monitoring in digital cellular systems |
| US5042082A (en) * | 1989-06-26 | 1991-08-20 | Telefonaktiebolaget L. M. Ericsson | Mobile assisted handoff |
| WO1992017953A1 (en) * | 1991-04-01 | 1992-10-15 | Motorola, Inc. | Target channel verification in a radiotelephone system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9510861D0 (en) | 1995-07-26 |
| AU5829096A (en) | 1996-12-18 |
| CN1191660A (en) | 1998-08-26 |
| WO1996038997A1 (en) | 1996-12-05 |
| AU701840B2 (en) | 1999-02-04 |
| EP0829179A1 (en) | 1998-03-18 |
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