CN1154614A - Code division multiple access system providing load and interference based demand assignment service to users - Google Patents

Abstract

A code division multiple access system provides a way of allocating an increased data rate to a requesting mobile station. A mobile station requesting a data rate in excess of the basic data rate sends received pilot strength data for its base station and base stations in adjacent cells. The received pilot strength data is used to determine an increased data rate to be assigned to the requesting mobile station. One feature assigns an increased data rate based on the predetermined relationship. Yet another feature utilizes a series of threshold levels, each pair of levels associated with a different permitted data rate. Using the received pilot strength data, a data rate is determined which satisfies all adjacent cell interference concerns. Another feature uses average adjacent cell capacity loads rather than threshold levels, together with the received pilot strength data, to determine the appropriate increased data rate to be assigned to a user requesting an increased data rate.

Description

The code division multiple access system of serving based on the distribution according to need of load and interference is provided for the user

The present invention relates to code division multiple access system, relate to specifically be the cdma system of user's distribute data speed according to the load and the interference of system.

The advantage of code division multiple access (CDMA) that is used for cellular voice communication is well-known.With compare such as the orthogonal system of time division multiple access (TDMA) or frequency division multiple access (FDMA), can be reduced at greatly between the unit and the unit in frequency ruleization or orthogonality coordination.Its reason is, reuses the interference that constraint must be considered (or 95 percent) under the worst case in TDMA or FDMA, and reuses the average interference that be based on obtains from a large amount of low-power users in CDMA.Because the average characteristics of this interference, CDMA converts the speech activity factor and antenna subregion to capacity gain simply.And the RAKE receiver determines the multipath parts of spread spectrum signal and it is converted to diversity gain.

Although these advantages are arranged, traditional cdma system has very limited unit user throughput and is unsuitable for the application of the Local Area Network etc. of " bandwidth on demand ".In fact, current CDMA standard is operated with circuit-mode, and the supposition user evenly distributes, and the user is restricted to only accounts on a fraction of speed of power system capacity.As mentioned above, CDMA depends on the average influence from a large amount of low rates (voice or circuit-mode data) user's interference.CDMA relies on complicated power control more and only accounts for sub-fraction from the interference of the user in the unit with all users' of guaranteeing adjacent cells average interference.Defective power control has direct influence to systematic function in homogeneous system.

Even best power control has been arranged, the high rate user in having the system of mixed service can cause a large amount of adjacent cells interference variations, and this variation meeting seriously reduces power system capacity.This problem is an impediment to high data rate service is provided in cellular system.

Transmission user and when system load allows, coordinate the peak data rate demand of high data rate user during distribution according to need technical protection voice based on load and interference of the present invention (with other high priority or delay-sensitive) etc.More particularly, method and apparatus of the present invention provides a code division multiple access system with a plurality of unit, and wherein each unit all has a base station and a plurality of mobile radio station, and the working method of this system is the higher data rate of mobile radio station distribution for the request of sending.Originally system receives a data burst request (data burst request) from a mobile radio station, and this mobile radio station has a high burst rate data call that exceeds the master data speed B that distributes to above-mentioned mobile radio station of having set up in a first module of requested data rates.Data burst request comprises the pilot strength information (for example, the pilot measurement reports message of IS-95) of base station being used for first module and at least one unit adjacent with first module.Suppose the load level in the known first module, an access controller uses the pilot frequency intensity that receives to determine whether to provide higher data rate with the mobile radio station that means the request of sending.If agreeing provides, then send a data burst allocation response to the mobile radio station of the request of sending from access controller.The pilot frequency intensity and the critical value (for example interference level indicating device) that have a function to allow access controller relatively to receive.When satisfying predetermined relationship between pilot frequency intensity that receives and the critical value, the indication of data burst assignment response provides higher data rate with the mobile radio station that means the request of sending.When having a plurality of adjacent cells (being also referred to as adjacent unit here), it is exactly first data rate of being asked that the pilot frequency intensity that receives in all base stations from a plurality of adjacent cells is no more than the data rate that increases under the situation of critical value.

Another function is then used a series of threshold values, and all different with one the permission data rate of each threshold values is correlated with.Utilize the pilot strength information that receives, can determine that is satisfied all adjacent cells interference predetermined data speed.According to another function, use average adjacent cells load rather than threshold values, and pilot strength information is determined to be assigned to and is asked the more data rate of the user's of high data rate suitable increase.

In the accompanying drawings,

Fig. 1 has illustrated the cdma system that can use current field of the present invention;

Fig. 2 has illustrated the module map of illustrative mobile radio station of the cdma system of relevant Fig. 1;

Fig. 3 has illustrated the module map of illustrative base station of the cdma system of relevant Fig. 1;

Fig. 4 has illustrated how the base station provides the flow graph of serving based on the distribution according to need of load and interference according to the present invention for the mobile subscriber;

Fig. 5 has illustrated how relevant switch-access controller coordinates the flow graph of soft handover between the unit;

Fig. 6 has illustrated the flow graph of relevant autonomous access control function of the present invention;

Fig. 7 has illustrated the flow graph of the autonomous access control function of relevant enhancing;

Fig. 8 has illustrated the flow graph of relevant adjacent cells coordinating access controlled function;

Fig. 9 has illustrated the illustrative legend of relevant data speed, and this data rate is as being allowed to offer a user with respect to the base station remote functionality;

Figure 10 has illustrated the illustrative legend of relevant reception pilot frequency intensity measuring at data rate multiple m.

For the potential large disturbance of reducing in the cellular CDMA-system of service mixed service changes, the present invention includes the autonomous and/or contract network access control of considering channel loading and interference.The present invention dynamically distributes higher data rate and adjusts each quality of services for users (QOS) according to demand for services simultaneously to the user.By allowing the user on a plurality of channels, to send simultaneously or gaining by using such as variable expansion, variable channel code rate, alternate manners such as variable letter section speed change modulation system (Walsh modulation, coded modulation, BPSK, QPSK ...) can distribute higher data rate for the user.Applying for by Richard D.Gitlin and Chih-Lin I, the United States Patent (USP) 5 that is entitled as " code division multiple access system that the variable-data-rate visit is provided " in issue on August 15 nineteen ninety-five, 442, described a kind of scheme that can realize this mode in 625, this scheme is to have the multiple encoding CDMA (MC-CDMA) that dynamic on-demand distributes.By on channel with a target frame error rate (FER) and signal to noise ratio (E _b/ N _o) carry out power control and can adjust QOS.In the present invention, network uses a kind of consideration channel loading in carrying out rate-allocation and QOS judgement, and the control strategy of interference and soft handover is to guarantee the desired priority of voice user.Distribution according to need visit dynamic like this, classes of packets makes that having different service-users can visit channel according to desired speed and QOS demand.

Above-mentioned autonomous network access control here is meant provides dynamic on-demand to distribute the distribution according to need based on load and interference (LIDA) of burst access in the radio CDMA network.Transmission user when LIDA can protect voice (with other high priority or delay-sensitive) etc., and under the situation that channel loading allows, allow high data rate user to carry out the peak rate visit.Under the assurance of best type QOS, the computer application that high data rate service is very suitable for common LAN type and wide area network WAN type (comprises the service (C.Perkins based on mobile IP, " IP moves support ", Internet Engineering Task Force, March 21 nineteen ninety-five) and CDPD (" cellular digital packet data system standard: version 1.1 ", CDPDForum, Inc., but not too be suitable for having the rate applications of strict real-time constraint January 19 nineteen ninety-five)).

In being described below, every or module all has an associated referential expression among all figure, and wherein this legend (for example 110 occur in Fig. 1) appears for the first time in the indication of first figure place.

With reference to Fig. 1, multiple encoding (MC) cdma system in a current field is described.This illustrative MC-CDMA system comprises one by unit 100,110,120,130,140,150 and the 160 regular hexagonal grids that constitute, wherein each unit comprises a plurality of mobile radio stations (for example MS1.1-MS1.N), these mobile radio stations make a plurality of users (1-N) base station BS 1 corresponding with it that can coexist in the cell site communicate by letter.Cell site 120 comprises base station BS 2 and mobile radio station MS2.1-MS2.J.

Can in such as each base station of BS1-BS2, realize the LIDA control of the present invention will be below described in the paragraph.In one embodiment of the invention, access controller 190 is used to provide coordinating access control (Fig. 1) at (for example between BS1 and BS2) between the neighbor base station.In such scheme, access controller 190 is higher than the data rate of basic rate and the distribution of burst length with all base station communications with control.Although provided access controller 190 on independent position, this access controller can be in the same place with a base station or center switch.

Wireless distances is the actual wireless loss that produces when sending to a mobile radio station from the signal that a base station sends.The pilot power Pi that receives at mobile radio station is P/z _i, wherein P is for sending pilot power z from each base station _iBe actual " wireless distances ".Because the mobile radio station MS1.1 in the unit 100 is near unit 120, the increase of the power level of the reception pilot tone of base station BS 2 also surpasses threshold values T _Add, mobile radio station then enters " soft handover ".During soft handover, mobile radio station is communicated by letter with BS2 with base station BS 1.In the present invention the use of the pilot measurement of controlling at burst access is expanded.

With reference to Fig. 2, the illustrative modules figure of a wherein given relevant mobile radio station MS1.1 comprises a transmitter station 250 and a receiver station 260.The illustrative example of mobile radio station has been described in the United States Patent (USP) of quoting in front 5,442,625.Transmitter station 250 comprises one with the convolution coder 201 of first bit-rate reception from user 1 digital information (or data-signal).Interleaver 202 and Walsh modulator 203 are linked in the output of convolution coder 201, and all these all are well-known in current field.Go here and there also (S/P) stand and 281 linked the outputs of Walsh modulator 203 and user's input digit information flow is changed into M master data multirate serial information flow.Below MC-CDMA is used as the illustrative method of the data rate that provides higher.

281 users' the serial digital information input of going here and there and stand converts the M data flow to, and (M is≤M _MaxInteger), wherein this input can be at most the M of basic source speed B _Max(M doubly _MaxB 〉=channel speed).The output at S/P station 281 is connected to coding expander 204,224 and 244, and it is unique encoding C that these coding expanders become to use for user 1 each M data flow respective extension ₁, C ₂And C _MChannel bit rate.Blender 254 hybrid coding expanders 204,224 and 244 output.Output signal blender 254 links to each other with 206 with encoder 205.In encoder 205, with a same code A _ITo further encoding from the signal of blender 254.Similarly, encoder 206 also uses a quadrature phase sign indicating number A _QTo signal encoding from blender 254.Sign indicating number A _IAnd A _QAll mobile radio stations for Fig. 1 are public.

The output of encoder 205 is used to modulated carrier signal Cos ω in modulator 208 _cT.The output of encoder 206 is used to modulated carrier signal Sin ω in modulator 209 _cT.In some applications, can use a relay station that better frequency spectrum shaping is provided.Modulator 208 and 209 output are mixed and be wirelessly transmitted to the wireless frequency signal of a base station (as the BS1 of Fig. 1) by antenna 211 in blender 210.

A base station (as BS1) sends on a different carrier frequency, and this carrier frequency is received and decoding by the mobile radio station MS1.1-MS1.N in its cell site 100.In illustrative example, the receiver 260 of mobile radio station MS1.1 comprises the demodulator (in figure do not provide) of a demodulation carrier frequency to obtain a channel bit rate signal, wherein uses coding A _IAnd A _QTo channel bit rate signal decoding and the relevant coded sequence C of use ₁It is carried out de-spread to obtain to be exported to user 1 information data signal.

Base station such as BS1 receives in the receiver 260 similar modes with mobile radio station MS1.1, decoding and de-spread user's 1 information data signal.Similarly, has a unique encoding C except user N _NSo that outside user 1 distinguishes mutually, other mobile radio station of being represented by mobile radio station MS1.N is to operate with the similar mode of mobile radio station MS1.1.In mobile radio station MS1.N, in-phase code and orthogonal coding A _I, A _QAnd carrier frequency f _eRespectively be used for the identical of mobile radio station MS1.1.

With reference to Fig. 3, wherein provide the illustrative modules figure of a relevant base station MS1.Modulated carrier signal is received and is handled by MC-CDMA receiver 302 under the control of processor 303 at antenna 301.Receiver 302 is to operate with the MC-CDMA receiver 260 similar modes of the mobile radio station MS1.1 of previously described Fig. 2.Similarly, MC-CDMA transmitter 305 is by antenna 311 transmissions and to operate with previously described transmission 250 similar modes.

The operation of the processor 303 control MC-CDMA receivers 302 under the program control that resides at memory 304, and MC-CDMA transmitter 305 is finished common base station functions and can be finished some or with good grounds distribution according to need based on load and interference of the present invention (LIDA) function by unit 100.Fig. 4-9 has illustrated this LIDA function, and following paragraph will be described this function.But do not discuss here and the function of finishing by base station BS 1 of understanding that the present invention has nothing to do.

Interference calculation

Continuation is at first studied in the unit that is brought by a high data rate user (use multiple encoding) He outside the unit and is disturbed with reference to Fig. 1.The result shows need make distribution according to need match with network control algorithm LIDA.Permission with the process of LIDA algorithm that reaches basic rate M speed doubly and carry out burst access usually based on following content:

Load information in unit and adjacent cells thereof;

The pilot frequency intensity measuring that provides by mobile radio station;

Burst rate between adjacent cells, the coordination of burst length and burst zero-time.

Can coordinate by the system resource that LIDA manages between data user that can carry out the high bit rate burst mode operation and high priority voice user.Provide LIDA algorithm below with different complexities.In order to simplify description, the control procedure at the system with independent data user is described here.The process that is used for a plurality of data users is very similar therewith.Controlling mechanism given here is necessary to provide a kind of shared burst mode access mechanism on CDMA, and this controlling mechanism application is become a new invention here.

In the following description, the CDMA Cellular System of supposing Fig. 1 has power control and includes only and is in each mobile radio station MS1.1-MS1.N, the voice user among the MS2.1-MS2.J.Consider cell site 100: when only providing service for the voice user, interference source in each unit produces same interference at base station BS 1 place, have only a user so seem, and in regular hexagonal grid cellular system 110-160 outside the averaging unit that all unit compile interference source (as MS2.1) look and resembled γ user.Suppose that path loss index is 4, γ is approximately 0.5.Have in N voice user's the system in every unit, total interference at each place, base station is:

I _o=α N (1+ γ) (1) wherein α is voice duty factor (speech activity factor).In follow-up discussion the specified interference I that has in the system of only voice that capacity is every unit N user _oBe used as with reference to QOS.

Studying is now having only a data user to sentence M times of interference in the unit under the situation that the speed of basic rate (depending on the reference system configuration, 9.6kbps or 14.4kbps) sends in the time ' t '.Suppose that voice duty factor α is approximately 0.4, under desirable power control, an active data user is equivalent to the individual voice user of 2.5M (=M/ α) in its unit.If M=4, then the data user takies the resource that is equivalent to 10 voice users, and " load of equal value " of promptly such data is 10.Under the situation of the common capacity with every unit 15-25 voice user, being very easy to find single high data rate user has bigger influence to cell capability.(obviously, a mobile radio station data user's duty factor can influence its average demand; And the distribution according to need of high data rate bursts must be considered during its high data rate transfer the maximum interference that produced by the data user.)

Consider influence below to interference outside the unit.Be evenly distributed in the system of only voice of unit 110-160 the voice user, disturb near the unit elementary boundary 111-161 (as MS2.1) that comes from other outside most unit.Because path loss index is bigger, apart from disturbing outside the less unit of the farther user in border (as MS2.N) generation.Because high data rate user (as MS1.1) doubly sends also along moving near the path 101 on border 121 to the speed of voice user's mean data rate with M/ α, remain near the M/ α disturbing in the unit of BS1, by the high data rate user produce to disturbing then fast above degree at voice system calculated BS2 the unit outside.Yet in order to keep required service quality (QOS), the total interference that must control each place, unit makes it to be not more than I _o

For above-mentioned discussion is quantized, suppose that there is N every unit _vIndividual voice user and effective (sending) high data rate user is arranged in master unit, total interference that can be expressed in so in master unit and the immediate adjacent cells is as follows:

I _d(r)=α Nv (1+ γ)+M γ _d(r) (2) wherein ' r ' for from enlivening the high data rate user to the distance its master unit website.Because this unit carries out power control and at its approaching adjacent cells γ is arranged _d(r)=1, for master unit γ is arranged then so _d(r) ≈ (2R-r) ⁴/ r ⁴Retrain below must satisfying at master unit with at high data rate user's access control mechanisms by approaching adjacent cells:

I _d(r)≤I _o(3), to attempt here the voice user is counted N in order to satisfy interference constraints _v, or the multiple M of the master data speed B of data user's use adjusts as the function of ' r '.Chapters and sections will be described relevant issues and strategy in detail below.

Utilize the Interference Control of pilot frequency intensity measuring

In the description in front, disturbing outside the unit that causes because of a data user is the function of (2R-r)/r.Access controller is determined the N that allowed to the distance of cell site according to relevant mobile radio station _vValue with M.When being used as control variables, ' r ' have two problems.First problem is accurately to determine the distance of mobile radio station to cell site.Come discussion unit to disturb although the more important thing is the front outward according to distance ' r ', actual interference depends on the blind area damp condition except that distance more.So based on the control of geographic distance neither best neither be feasible.The present invention has used a kind of based on wireless distances and utilize pilot frequency intensity measuring to solve the control of two problems.This scheme can easily become an integral part of cdma system.

In current cdma system, realize supporting mobile soft handover in the following manner.The base station provides an adjacent pilot frequencies tabulation for mobile radio station.Mobile radio station is periodically measured the pilot frequency intensity on its neighbor lists and it is sent to cell site.If the pilot frequency intensity of the base station that mobile radio station is not connected to is greater than a threshold values T _Add, then the base station is soft handover of mobile station initialization.The present invention has expanded and has utilized pilot frequency intensity measuring to carry out notion that soft handover judges and it is used for the access control of high data rate user.

With reference to Fig. 4, the cdma system of the described LIDA ability of having of Fig. 1 (after this being called LIDA) is described here.In step 401, a mobile radio station produces the calling of a request high data rate bursts mode service option.In step 403, the high modulation demodulator speed of mobile radio station and base station negotiate and at the Maximum Burst Size of mobile radio station.

Shown in step 405, each user is assigned with one and is confirmed as specific to the unique primary coding of user's PN sequence, i.e. C ₁When the user is static 407, utilize its primary encoder to safeguard the very low signaling channel of a speed (the 8th speed) (sub-speed).This sub-rate channel helps maintain synchronization and the control of coarse adjustment power.Wherein the user " links to each other " with a base station or carrying out the such situation of soft handover in a plurality of unit also obtains safeguarding.Because the transmission during the 8th rate frame is intermittently, it is inadequate that then synchronous and power is controlled under the very long situation of quiescent phase.

Thereby any transmission from mobile radio station after one section long quiescent phase 407 all might be lost.Can overcome this problem by the synchronization burst 409 that requires mobile radio station when " length " quiescent phase finishes, to send (or more a plurality of) basic rate frame.The synchronization burst back of carrying out synchronous time and power Control and Feedback is being provided for receiver, and mobile radio station is by the request 411 of basic rate (B) channel usage signaling message transmission at data burst transmission.Alternatively, except in step 407, outside 409 the synchronization burst, can require mobile radio station repeatedly to send request 411.

Access request 411 from mobile radio station comprises the data rate and the burst length of being asked.Determine the Maximum Burst Size that mobile radio station can ask (and select to be used between the optimum coordinates user share and access) by system.In addition, in order to provide interfere information, comprise pilot strength information (at the base station of the unit in its neighbor lists, MS1.1 can comprise the pilot frequency intensity measuring of the base station of relevant unit 110-160) such as PMRM from the access request of mobile radio station to the base station.(notice that being included in the access request for the report that is used to handle soft handover is independent (in addition) to pilot frequency intensity measuring.) measuring from the pilot length of mobile radio station (as MS1.1) reception can be at the interference level of adjacent base station (as BS2) generation to base station (as BS1) indication mobile radio station.This interferometry considered apart from the decay of loss and blind area, thereby also is a kind of measurement to the distance that arrives adjacent base station, and this measurement control that will be used to conduct interviews in step 413 is judged.

Say definitely, when the blind area decay occurs, according to people's such as K.S.Gilhousen, be entitled as " about the capacity of cellular CDMA-system " (IEEETrans.Veh.Technol, Vol.VT-40, No.2, in May, 1991,303-312 page or leaf) book in the equation 1 described can improve in the average interference at the cell site place of the fundamental system of voice only.Here this equation is expressed as $I_0^s=\mathrm{\&alpha;N}(1+{\mathrm{\&gamma;}}^s),$ γ wherein ^sBe to disturb outside the averaging unit when the blind area decay occurring.Similarly, in the system of an integrated speech and data, be at the interference factor of a data user in the adjacent cells ${\mathrm{\&gamma;}}_d^s({\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="A9611271600221.png,A9611271600241.png"\; state="\{\{state\}\}">z</figure-callout>}}_1,z_2)={\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="A9611271600221.png,A9611271600241.png"\; state="\{\{state\}\}">z</figure-callout>}}_1/{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="A9611271600272.png"\; state="\{\{state\}\}">z</figure-callout>}}_2,$ Z wherein ₁And Z ₂Be respectively the path loss that mobile radio station arrives master unit and adjacent cells.Note because power is controlled under the situation of master unit ${\mathrm{\&gamma;}}_d^s({\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="A9611271600221.png,A9611271600241.png"\; state="\{\{state\}\}">z</figure-callout>}}_1,z_2)=1$ 。Path loss (wireless distances) z ₁And z ₂Comprise apart from loss part and blind area decay part.Interference constraints becomes: $I_d^s({\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="A9611271600221.png,A9611271600241.png"\; state="\{\{state\}\}">z</figure-callout>}}_1,z_2)=\mathrm{\&alpha;}{N}_v(1+{\mathrm{\&gamma;}}^s)+M{\mathrm{\&gamma;}}_d^s({\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="A9611271600221.png,A9611271600241.png"\; state="\{\{state\}\}">z</figure-callout>}}_1,z_2)----\left(4\right)$ $\&le;I_0^s$ Its intermediate value z ₁And z ₂From pilot frequency intensity measuring, derive.

As shown in Figure 5, come completing steps 413 by the base stations (or the base station under the situation of soft handover) or an access controller of an independent position that is arranged in by 190 expressions of Fig. 1.In step 415, this distribution is sent to mobile radio station.If dispatch list is longer than threshold values L, then mobile radio station is apprised of retry (retry delay) in step 415 after this.The base station is according to the value of selecting this parameter at the load state at this place, base station.When mobile radio station received delay parameter in data burst assignment messages 415, it was with distribute data speed, and step 421 starts it and distributes burst length transmission, such delay of initialization before the step 417.In an optional embodiment, can require explicit BEGIN message of mobile stations wait with the beginning high data rate transfer.

With reference to Fig. 1, how 4 and 5 description of access control devices coordinate the burst access of a mobile radio station (as MS1.1) during the adjacent base station BS2 in base station BS from unit 100 1 and unit 120 carries out soft handover.Carry out step 409 in the above described manner, 411 and 415.Fig. 5 has illustrated that a burst that is sent to access controller accepts message 501, and this controller is finished treatment step required during soft handover 413.With reference to Fig. 6, in 7 and 8 the paragraph these treatment steps will be described in more detail afterwards.After handling, access controller sends the order of a data burst allocation to two base stations, step 503, and these two base stations then send data burst assignment messages 415 to the mobile radio station of the request of sending.

Autonomous access control

With reference to Fig. 6, autonomous access control function of the present invention is described here.Described in preceding step 411, mobile radio station provides pilot frequency intensity measuring (as PMRM) in access request.If the load state of master unit is very near a predetermined load level, step 600 then sends a retry delay order at step 600a.If the load state of master unit allows a burst access, but mobile radio station is in the soft handover, step 601, and then access controller is restricted to mobile radio station on the master data speed B (being multiple m=1).Allow m times of burst allocation message to be sent to the mobile radio station of the request of sending in step 605 to the data of basic rate B.If the master unit load state allows to carry out burst access and mobile radio station is not in soft changing state, then carry out step 607.At the definite base station pilot ionization meter of step 607 at all adjacent base stations ' i '.Be that all base stations ' i ' constitute pilot frequency intensity measuring P/z in neighboar lists _i(411 PMRM), wherein P is the known transmission power level of base station, and z _iBe path loss or wireless distances.If P/z is lower than a high data rate visit threshold values T _Hra, this indication mobile radio station can not produce undue interference to adjacent base station, and allows (step 609) mobile radio station to send a speed, and this speed is multiple M or the maximum multiple M that is asked _RMinimum value.As described in the patent of quoting previously, mobile radio station and base station can utilize son coding to interlock in local the generation to carry out doubly that the required M of speed transmission encodes in cdma system.In step 605, access controller sends burst allocation message to the mobile radio station of the request of sending.

Here select threshold values T by this way _Hra, the total interference from the mobile radio station of the request of sending that makes promptly what adjacent base station place in office receives is lower than I _oAttention is in order to adapt to the high data rate user, and system can limit the voice user and count N _vMake it the maximum number that allowed less than in the system of voice only.Improving T _HraWith minimizing N _v, exist a kind of compromise between every unit users number.

If determine to allow the mobile radio station of the request of sending to send with two-forty, then burst transfer can be adjusted in the base station.Because load and disturbance regime can change along with the time, the judgement that whether allows is only being depended on system load, among the time period Q of blind area decay dynamic change and user mobility effectively.This time, Q was corresponding to the L frame duration.The base station is checked its scheduling burst table and in short-term the mobile radio station of having sent out the request that is issued is added in this table than L frame at this table.

If any one in the definite adjacent base station pilot frequency intensity (P/z) of step 607 is higher than threshold values T _Hra, then send with basic rate B at step 603 a permission mobile radio station.Here will not allow the mobile radio station of the request of sending to carry out the two-forty visit up to finding that all adjacent base station pilot frequency intensities are lower than T _HraThe judgement of attention soft handover is carried out respectively.The increase of soft handover and cancellation threshold values T _AddAnd T _DropUsually be not more than high data rate visit threshold values T _HraDescribed in step 601, the mobile radio station that is in soft handover only is allowed to send with basic rate B (being m=1).Any transmission of carrying out with basic rate B does not need to authorize as required.

This autonomous access control is attractive because of its simplification, but wherein still has some restriction.For example, mobile radio station can be in soft changing state in the major part of overlay area.Even below will provide the scheme that during soft handover, also can allow the two-forty visit.

Strengthen autonomous access control

With reference to Fig. 7, the autonomous access control function of enhancing is described here.Previously described autonomous access control only allows two kinds of data rates to select, and mainly is basic rate (m=1, step 603) and two-forty, and wherein two-forty is rate request M of institute or the maximum rate M of system _RThe minimum value of (step 609).Strengthen autonomous access control function and produce a plurality of threshold values, the overlay area that these threshold values increase the high data rate user exceeds basic rate B twice feasible can the distribution, and three times ... the speed of (or even non-integer multiple).The user who asks high data rate more like this concentrates at it usually and is assigned with a higher data rate when being positioned at its unit, and is assigned with a lower data rate during near an elementary boundary at them.

At step 700 and 700a, with in step 600 and 600a similarly mode check the load state of master unit.If mobile radio station (as MS1.1) is in soft changing state, then to carry out step 703 and 705 with step 603 and 605 similar modes.If but mobile radio station is not in soft changing state, access controller utilizes step 707 to select a data speed.In step 707, according to the definite maximum length of lead P/z of pilot frequency intensity measuring collection that reports in step 411 by mobile radio station MS1.1 from all base stations ' i ' in the adjacent cells _iAccess controller is with maximum pilot frequency intensity and threshold values collection (T as shown in figure 10 _m, m=0,1 ... M _R) compare T wherein _m＞T _M+1Each threshold values T _mCorresponding to a different permission data rate multiple m.In order to be consistent T _o=P and T _Ma=T _HraShown in step 703, if the pilot frequency intensity P/z of any adjacent base station all is not less than threshold values T ₁, then 1 of the base station BS of mobile radio station MS1.1 allows it to conduct interviews with basic rate B (m=1).If maximum pilot frequency intensity P/z is between T _mAnd T _M-1Between, then select data rate multiple m so that the interference of locating in the base station of any adjacent cells is lower than I in mode shown in Figure 10 _oIn step 709, access controller selects data rate multiple m to make it to be not more than system specialization value M _RWith the multiple M that is asked.In step 705, burst allocation message 503 comprises speed multiple m.As previously mentioned, its scheduling burst table is checked in the base station, mobile radio station is increased in its required list under at this table than the short situation of L frame, and to mobile radio station transmission assignment messages 415.If dispatch list is longer than threshold values L, inform in message 415 that then mobile radio station is at retry after this.

In addition, if the pilot frequency intensity of any adjacent base station is all greater than threshold values T in step 707 ₁, mean that then the high rate data transmission from mobile radio station MS1.1 can cause extra interference in adjacent cells.Thereby mobile radio station is limited to the basic rate (m=1) shown in step 703.

The invention enables one to concentrate the location or be positioned and one or morely can independently determine maximum ' m ' value corresponding to ' m ' times basic rate B such as the access controller in the base station of BS1, wherein mobile radio station MS1.1 doubly sends to the speed of basic rate B with ' m ', and this ' m ' value satisfies following interference constraints: $\mathrm{\&alpha;}{N}_v(1+{\mathrm{\&gamma;}}^s)+m{\mathrm{\&gamma;}}_d^s({\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="A9611271600221.png,A9611271600241.png"\; state="\{\{state\}\}">z</figure-callout>}}_1,z_2)\&le;I_0^s-----\left(5\right)$ Wherein for master unit ${\mathrm{\&gamma;}}_d^s({\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="A9611271600221.png,A9611271600241.png"\; state="\{\{state\}\}">z</figure-callout>}}_1,z_2)=1$ 。Definition threshold values T _mSatisfying at bit rate multiple m=1,2 ..., up to M _REquation 5.And the mobile radio station that only allows to be in soft changing state sends with basic rate (m=1); Wherein do not need extra negotiation between the unit of soft handover relating to.

Compare with the single valve value scheme of Fig. 6, the enhanced scheme of Fig. 7 only need increase a bit extra complexity.

With reference to Fig. 9, wherein provided a legend, the data rate that the mobile subscriber of this marginal data in the unit with 25 voice users allows is how with the function of the distance that arrives the base station, supposing has 21 users to be in soft changing state.Fig. 9 illustrates that these critical values 901-904 is quite approaching each other and possibly can't be distinguished from each other in the noise pilot frequency intensity measuring; And according to from the gauged distance of base station from m doubly the decline to the interference accepted (902-904) of the speed of basic rate B to the interference accepted (901) of basic rate B be fastish.

Adjacent coordinating access control

With reference to Fig. 8, adjacent cells coordinating access controlled function is described here.Above-mentioned two kinds of schemes are not all considered occurent load in the adjacent cells.Described in following paragraph, can utilize the underload in the adjacent cells also still to satisfy interference constraints Is0 with the visit that allows to carry out higher rate.

When mobile radio station MS1.1 linked to each other with an independent base station BS 1, base station BS 1 was known, step 802, and the load of adjacent cells helps to carry out rate-allocation at a high data rate access request 411 and judges.In step 803, average load is calculated in the base station In step 805, do not use fixedly threshold values, base station BS 1 carries out rate-allocation at the minimum ' m ' of all adjacent base stations and the inequality of itself and judges below determine satisfying: $\mathrm{\&alpha;}(N_v^i+{\stackrel{-}{N}}_v{\mathrm{\&gamma;}}^s)+m{\mathrm{\&gamma;}}_d^s(z_l,z_i)\&le;I_0^s----\left(6\right)$ Wherein Be every unit voice user's average in the adjacent cells, N _v ⁱBe audio call number in the unit ' i ' and z _iBe " wireless distances " of data user base station of ' i ' to the unit, wherein ' i ' is the index of adjacent cells tabulation.Master unit is corresponding to i=1.In fact, for each adjacent cells, value N _v ⁱShould be counted as " load of equal value " audio call.By selecting to satisfy minimum ' m ', can guarantee that doubly carrying out burst access to the speed of basic rate B can not cause extra interference on any adjacent cells with ' m ' in permission at the equation 6 (step 805) of all adjacent cells ' i '.In this case, the communication of unique needs is that adjacent cells periodically provides the renewal to its present load, step 802.In step 807, multiple ' m ' is chosen to m _i, M and M _RMinimum value.In step 809, if, then provide rate-allocation and burst parameter for mobile radio station in step 811 if mobile radio station is not in soft changing state and dispatch list is shorter than L frame; Otherwise inform the mobile radio station retry in step 811.

When step 809 mobile radio station is in soft changing state, all continuous base stations all receive access request (comprising pilot frequency intensity measuring).The simplest strategy is to allow mobile radio station only send with basic rate (not being with access control) when it is in soft changing state.In order in soft handover, to allow higher data rate, between adjacent base station, be necessary to carry out more complicated coordination.Each base station carry out with step 805 in similarly calculate to determine the maximum speed ' m ' that allows, maximum burst length and the Earliest Starting Time of allowing.But not that this distribution is sent to mobile radio station, but in step 813, this information is passed to the access controller that is positioned at " elementary " base station or center switch place (Fig. 1 190).The distribution that controller 190 is relatively made by each base station is also selected rate-allocation and by minimum value in the burst length of soft handover unit suggestion and nearest suggestion start-up time.This controller is then created assignment messages (Fig. 5 503) and it is sent to the mobile radio station (step 415 of Fig. 5) that is in soft changing state.If any one in the base station pointed out the long and necessary retry of mobile radio station of its dispatch list, then send a retry message to mobile radio station in step 415.Note, because controller 190 necessary selections must carefully avoid influencing the channel utilization in the related unit of soft handover by the minimum value of the speed of different units permission and nearest start-up time.

When the present invention is implemented as the MC-CDMA system with LIDA, wherein have following characteristic:

The data, services (for can be up to 56kbps based on the CDMA of IS-99 and relevant criterion) of high access bandwidth is provided under the prerequisite of minimum change IS-95 wave point and IS-99 data standard.

As described in the patent of quoting previously, it is chain that the present invention is more suitable for being used for the son coding.

The high bandwidth distribution according to need of each burst access is foundation with load and channel conditions.

Access control in the network guarantees voice and other high priority user's priority.

Handle makes the coding based on transmitter be used for dedicated receiver on each connects.

In order to use ARQ to repeat transmission to reduce E _b/ N _oDemand and increase capacity have been sacrificed (some) forward error corrections (FEC).

Though above-mentioned controlling schemes provides the two-forty visit that utilizes MC-CDMA, the controlling schemes LIDA that is provided is transparent, and can be applicable to equally in the physical layer of the high data rate visit that any realization undertaken by CDMA.

The description of front is just in order to illustrate the application of principle of the present invention.Those skilled in the art can realize other scheme and method under the prerequisite that does not depart from aim of the present invention and scope.

Claims (25)

1. comprise that at one a plurality of unit and each unit have in the code division multiple access system of a base station and a plurality of mobile radio stations, the method for mobile radio station distribution bandwidth comprises the steps:

In the data pulse string request of a base station of first module place's reception from the mobile radio station of above-mentioned first module, request surpasses first data rate of the master data speed B distribute to this mobile radio station, and above-mentioned data burst request comprises the pilot strength information at a base station of the base station of above-mentioned first module and at least one unit adjacent with above-mentioned first module;

At an access controller place, the pilot strength information that utilize to receive is determined a data rate that is increased, and this speed is assigned to above-mentioned request mobile radio station under the situation that above-mentioned first module and above-mentioned at least one adjacent cells is not produced extra interference;

Send the data burst assignment response has been assigned to the increase of above-mentioned request mobile radio station with indication data rate from access controller to the above-mentioned mobile radio station that sends request.

2. the method for claim 1, wherein

The pilot strength information that access controller relatively receives and a threshold values, and give above-mentioned request mobile radio station a data rate allocation that increases when between the pilot frequency intensity that receives and this threshold values, satisfying predetermined a relation.

3. method as claimed in claim 2, wherein

Base station in being in the adjacent unit of a plurality of and above-mentioned first module provides pilot strength information, and

Give first data rate when being no more than threshold values when any one base station reception from a plurality of adjacent cells and by above-mentioned pilot frequency intensity of asking the mobile radio station report for instructions.

4. the method for claim 1, wherein

Burst request comprises the data burst length information, and

The data burst assignment response comprises a data burst length parameter to the data burst length of regulation request mobile radio station permission.

5. method as claimed in claim 4, the step that wherein above-mentioned base station comprises has

Determine whether requested burst length information is allowed to, and when allowing, in the data burst assignment response, comprise a permission data burst length parameter.

6. the method for claim 1, wherein the data burst assignment response comprises that the indication request mobile radio station should be in the retry delay information of its request of retry after this.

7. the method for claim 1, wherein the data burst assignment response comprise that the mobile radio station of request is sent in indication should be the start delay information of its transmission lag a period of time, the time of delay can obtain from start delay information.

8. the method for claim 1, the step that wherein also comprises has checks a data dispatching burst tabulation at base station place, wherein the data burst assignment response comprises after when this table is longer than a predetermined length one retry message and data when this table is shorter than the predetermined length permission message that happens suddenly.

9. method as claimed in claim 2, wherein threshold values is one and is lower than soft handover and increases (T _Add) and reduce (T _Drop) the two-forty visit threshold values (T of threshold values _Hra).

10. method as claimed in claim 2, wherein threshold values is one and increases (T _Add) and reduce (T _Drop) have the two-forty visit threshold values (T of predetermined relationship between the threshold values _Hra).

11. method as claimed in claim 2, the step that wherein also comprises has

When being higher than threshold values, the pilot strength information of any reception sends a data burst allocation response to the above-mentioned mobile radio station that sends request, the pilot strength information that receives during less than threshold values the data burst assignment response enable at the mobile radio station place of the request of sending, this speed is lower than the message transmission rate of the data rate of permission.

12. method as claimed in claim 2, wherein the data burst assignment response indicates first data rate to be rejected when pilot strength information surpasses threshold values.

13. the method for claim 1, wherein access controller is positioned among the one or more base stations that comprise first module.

14. the method for claim 1, wherein access controller is not among any one base station.

15. the method for claim 1, wherein one group of threshold values is relevant with a plurality of data burst speed, and access controller gives the above-mentioned data rate that sends the mobile radio station of request comparing with this group critical value from the pilot frequency intensity of above-mentioned at least one adjacent cells reception to determine one.

16. method as claimed in claim 15, wherein this group threshold values all has an associated data burst speed, and access controller is compared the maximum of the pilot length that receives from above-mentioned at least one adjacent cells and given the above-mentioned data rate that sends the mobile radio station of request with definite one with this group threshold values.

17. the method for claim 1, the step that wherein also comprises has:

Receive an adjacent cells load updating message at the access controller place, this message indication is in the load measure information at above-mentioned at least one adjacent cells place;

At the access controller place, the pilot strength information and the load measure information that utilize to receive are determined a data rate that is enhanced, and this speed is assigned to the above-mentioned mobile radio station that sends request under the situation that above-mentioned first module and above-mentioned at least one adjacent cells is not produced extra interference;

Be given the above-mentioned mobile radio station that sends request from access controller to the data rate that the above-mentioned mobile radio station that sends request sends after the data burst assignment response improves with indication.

18. method as claimed in claim 17, the step that wherein also comprises has:

At the access controller place, calculate the minimum ' m ' satisfy following inequality at all adjacent base stations ' i ', $\mathrm{\&alpha;}(N_v^i+{\stackrel{-}{N}}_v{\mathrm{\&gamma;}}^s)+m{\mathrm{\&gamma;}}_d^s(z_l,z_i)\&le;I_0^s$ , wherein Be the average load that is equivalent to adjacent every unit voice user, N _v ⁱBe the load that is equivalent to the audio call in unit ' i ', and z _iBe the data user to the unit wireless distances of ' i ', this wireless distances can derive from pilot measurement, wherein ${\mathrm{\&gamma;}}_d^s(z_l,z_i)=z_i/z_l$ ；

Send a data burst allocation response to indicate a data speed mB to be given the mobile radio station of the request of sending from access controller to the above-mentioned mobile radio station that sends request.

19. method as claimed in claim 17, wherein when a mobile radio station during with more than one base station communication in a plurality of unit,

At the access controller place, pilot strength information and load measure information that utilization receives from more than one base station are determined a data rate that is enhanced, not to a plurality of unit under the situation of the generation extra interference in unit adjacent with any and a plurality of unit this speed be assigned to the above-mentioned mobile radio station that sends request;

From the data rate of access controller after the above-mentioned mobile radio station that sends request sends the data burst assignment response has been given the above-mentioned mobile radio station that sends request with indication raising.

20. method as claimed in claim 19, wherein access controller determines that each base station allows the data rate that is enhanced that uses, and therefrom selects minimum data rate and sends selected minimum data rate to the above-mentioned mobile radio station that sends request.

21. one comprises that a plurality of unit and each unit have the code division multiple access system of a base station and a plurality of mobile radio stations, this system comprises:

Receive the receiving system of data burst request of this mobile radio station of above-mentioned first module that surpasses first data rate of the master data speed B that distributes to mobile radio station from request at the place, base station of first module, above-mentioned data burst request comprises the pilot strength information at a base station of the base station of above-mentioned first module and at least one unit adjacent with above-mentioned first module;

An access controller, the pilot strength information that this controller utilization receives determine that the data rate of an increase that will give the above-mentioned mobile radio station that sends request under the situation that above-mentioned first module and above-mentioned at least one adjacent cells is not produced extra interference and the data rate that sends after indication improves to the above-mentioned mobile radio station that sends request have been given the above-mentioned data burst assignment response of sending the mobile radio station of request.

22. code division multiple access system as claimed in claim 21, wherein

The pilot strength information that access controller relatively receives and a threshold values, and give the above-mentioned mobile radio station that sends request a data rate that improves when between the pilot frequency intensity that receives and this critical value, satisfying predetermined a relation.

23. code division multiple access system as claimed in claim 21, wherein

One group of critical value is relevant with a plurality of data burst speed, and access controller is given the above-mentioned data rate that sends the mobile radio station of request comparing with this group critical value from the pilot frequency intensity of above-mentioned at least one adjacent cells reception to determine one.

24. code division multiple access system as claimed in claim 21, wherein

Access controller receives the adjacent cells load updating message of an indication in the load measure information at above-mentioned at least one adjacent cells place, utilize the pilot strength information and the load measure information that receive to determine that one can not give the above-mentioned data rate that is enhanced that sends the mobile radio station of request under the situation to above-mentioned first module and above-mentioned at least one adjacent cells generation extra interference, and the data rate that sends after the data burst assignment response improves with indication to the above-mentioned mobile radio station that sends request has been given the above-mentioned mobile radio station that sends request.

25. code division multiple access system as claimed in claim 21, wherein

Access controller calculates the minimum ' m ' satisfy following inequality to all adjacent base stations ' i ', $\mathrm{\&alpha;}(N_v^i+{\stackrel{-}{N}}_v{\mathrm{\&gamma;}}^s)+m{\mathrm{\&gamma;}}_d^s(z_l,z_i)I_0^s$ , wherein

Be the average load that is equivalent to adjacent every unit voice user, N _v ⁱBe the load that is equivalent to the audio call in unit ' i ', and z _iBe the data user to the unit wireless distances of ' i ', this wireless distances can derive from pilot measurement, wherein ${\mathrm{\&gamma;}}_d^s(z_l,z_i)=z_i/z_l$ Send a data burst allocation response to indicate a data speed mB to be given the mobile radio station of the request of sending from access controller to the above-mentioned mobile radio station that sends request.

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