CN1154778A - Changing a service option in a CDMA communication system - Google Patents
Changing a service option in a CDMA communication system Download PDFInfo
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- CN1154778A CN1154778A CN 96190568 CN96190568A CN1154778A CN 1154778 A CN1154778 A CN 1154778A CN 96190568 CN96190568 CN 96190568 CN 96190568 A CN96190568 A CN 96190568A CN 1154778 A CN1154778 A CN 1154778A
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Abstract
A code division multiple access (CDMA) communication system (100) implements a service option change in a mobile station (106) by including data representing the service option to be employed in a handoff message (500) transmitted from a base station (102) to the mobile station (106). Use of the handoff message (500) as a medium to change a service option eliminates the cumbersome negotiation technique currently required to perform a service option change prior to handoff of the mobile station (106) from a first coverage area (104) to a second coverage area (110) or from a first channel to a second channel within a given coverage area (104).
Description
The present invention relates to code division multiple address communication system, particularly change service selection distribution in the code division multiple address communication system.
Code division multiple access (CDMA) communication system has been well-known.In cdma communication system, the communication between two communication units (for example a central communication base station and a mobile comm unit) is to utilize user's extended code of a uniqueness to expand realization by each being sent out signal on the frequency band of communication channel.Be sent out on the identical frequency band that signal is in communication channel owing to expansion makes, and only use unique user's extended code to come separately.These unique user's extended codes are preferably orthogonal, so that " cross-correlation " between extended code is approximately zero.In view of the above, when user's extended code was orthogonal, received signals can be relevant with specific user's extended code, so that only required subscriber signal (relevant with this particular extension sign indicating number) is by de-spread.
Those skilled in the art will be appreciated that having several different extended codes can be used for data-signal is separated from each other in cdma communication system.These extended codes include, but is not limited to pseudo noise (PN) sign indicating number and walsh code (Walsh code).A walsh code correspondence the single row or column of Hadamard matrix.For example, in one 64 channel CDMA spread spectrum spectra system, can from one 64 one group of 64 walsh code taking advantage of the 64Hadamard matrix, choose orthogonal specific walsh code.Simultaneously, by using a specific walsh code one specific data signal and other data-signals can be separated so that expand this specific data signal.
Those skilled in the art also will be appreciated that, extended code can be used for the channel code data-signal.Be sent out signal and can bear influence better by making, data-signal is carried out chnnel coding, to improve the particularly performance of mobile phone communication system of communication system such as the various radio telephone channel impairments of noise, decline and interference.Typically, chnnel coding has reduced bit error rate, and/or has reduced and be represented as every noise density bit energy (E usually
b/ N
o) the ratio of desired signal and noise, carry out the recovery of signal as cost to use than sending the required bigger bandwidth of this data-signal.For example, before the modulation of the data-signal that sends continuously, walsh code can be used for the channel-encoded data signal.Similarly, also pseudo noise (PN) extended code can be used for the channel-encoded data signal.
Typical C DMA transmission relates to the bandwidth of spread information signal, the signal that sends this expansion with by the spread-spectrum that receives again map become the bandwidth of original information signal to recover required information signal.This bandwidth transaction sequence of using in the CDMA transmission makes cdma communication system can transmit the information signal of relative zero defect in many noise signals environment or communication channel.From the quality of the recovery that is sent out information signal of communication channel is by at certain E
b/ N
oUnder error rate (that is, this is sent out the quantity of mistake in the recovery of signal at a specified time interval or during being received bit interval) weigh.When error rate increases, the signal quality that is received by the recipient will descend.As a result, communication system typically is designed to error rate is restricted to a upper limit or maximum, so that the degenerating of quality of received signals limited.
In current cdma communication system, such as (＂ both sides' formula wide-band spread spectrum is composed the travelling carriage-base station compatibility standard ＂ of cellular system by the IS-95A that is used for Digital Cellular System (DCS), publish by Electronic Industries Association (EIA), 2001 Eye Street, N.W., Washington, D.C.20006) definition and by the cdma communication system of the ANSI-JSTD-8 definition that is used for PCS Personal Communications System (PCS), based on the formation of its software and hardware, the capacity of base station and travelling carriage can be different.Such example is to come its definition with TSB58 in the scope of available service selection (being used for IS-95A).Each service selection is by the data definition of this service selection of expression, and as defined at the TSB58 that is used for IS-95A, described data are 16 bit fields of an expression service selection.
Each service selection does not also require all and will be supported by each operator of DCS/PCS.Therefore, when a travelling carriage of communicating by letter with home base stations enters the DCS/PCS that does not support the service selection supported by this this locality DCS/PCS, then this home base stations is required to send message to this travelling carriage, to change in the service selection of being supported by this target DCS/PCS.In the enforcement in DCS/PCS, the process of current change service selection is a kind of trouble, negotiation technology consuming time, is that a kind of and transparent travelling carriage is crossed the incompatible technology of purpose that switch in the district.Should be noted that to be that this technology itself is a trouble; For DCS/PCS, when comprising that the district switched, it is fully incompatible that whole service selection change/mistakes is distinguished task switching.
For example, when the base station when travelling carriage sends out a proposal and carries out the ＂ business request information ＂ of change of service selection, current requirement changes the technology of service selection and starts working.The maximum period of time that IS-95A allows travelling carriage to respond this information was 5 seconds.This travelling carriage responds by a ＂ service response message ＂ then, accepts the change of proposed service selection.For this message, the base station can be waited for and is 0.2 second to the maximum.Then, the base station sends the professional connection message ＂ of a ＂, and this message comprises the data representation of the service selection that will be used.For this message, travelling carriage can be waited for and be 0.4 second to the maximum.At last, travelling carriage is finished message ＂ by the professional connection of a ＂ and is responded, and the change that this message informing BTS service is selected is finished.At this moment, the base station enlarged district hand off direction message ＂ with a ＂ and sent to travelling carriage.May be because once cross district's switching with 0.4 second, so whole Negotiation Technology (changing to the district from service selection switches) may cause the aerial ＂ dead time ＂ until 6 seconds.The amount of this aerial ＂ dead time ＂ will make travelling carriage postpone to enter soft handover, the result that this has caused the increase system interference and has correspondingly reduced power system capacity.
In view of the above, need a kind of method and apparatus that does not influence power system capacity in order in cdma communication system, to change service selection effectively now.
Fig. 1 generality illustrates a kind of cdma communication system that changes according to service selection of the present invention that helps using.
Fig. 2 illustrate synoptically a kind of with help implementing mode of the present invention with the receiver cdma communication of a base station in the transmitter of travelling carriage.
Fig. 3 illustrate synoptically a kind of with favourable enforcement mode of the present invention with the receiver cdma communication of a travelling carriage in the transmitter of base station.
Fig. 4 illustrates the protocol hierarchy structure that is used for a kind of cdma communication system synoptically.
Fig. 5 illustrated according to a kind of " enlarging district's hand off direction message " with service selection data representation of the present invention.
Code division multiple access (CDMA) communication system is switched the message by the data of the expression service selection that will use being included in from the base station to the district of crossing that travelling carriage sends, and implements service selection and change in travelling carriage.Used the district to switch message and eliminated the Negotiation Technology of current required trouble, so that carry out service selection before switching and change in travelling carriage district of crossing from first overlay area to second overlay area or from first channel to second channel in a given overlay area as the media that changes service selection.
Service selection in code division multiple access (CDMA) communication system is normally at first determined to represent the data of the service selection in pre-stored message to change by the service selection of a travelling carriage use with to this travelling carriage transmission in travelling carriage.In this preferred embodiment, the data of representing service selection are 16 bit fields of one of a plurality of service selection of expression, and pre-stored message is one and crosses district's switching message that particularly a ＂ enlarged district hand off direction message ＂.In addition, in this preferred embodiment, the transmission of the data representation of service selection is transparent for the physical layer of transmitting thereon in the pre-stored message.
With reference to figure 1, can advantageously use a kind of cdma communication system 100 that changes according to service selection of the present invention shown in the figure.First base station 102 is positioned at one first overlay area 104, and communicates by letter with a travelling carriage 106.Communication is carried out through digital radio channel 108, and this digital radio channel 108 comprises the data message with the cdma communication system compatibility that is defined by IS-95A.Travelling carriage 106 will keep and the communicating by letter of this first base station 102, till travelling carriage 106 is near second overlay area 110.
Because travelling carriage 106 near first overlay area 110, is crossed the district from the honeycomb of 102 to second base stations 112, first base station and is switching to necessary.In CDMA, the feature that is known as ＂ soft handover ＂ is supported.During soft handover, it is prenoticed in second base station 112 is that honeycomb is crossed the target that switch in the district, and therefore uses the transmission mode of communicating by letter with first base station 102 to its notice travelling carriage 106.Second base station 112 will begin with identical transmission mode to send to travelling carriage 106, and travelling carriage 106 will carry out detection/demodulation to the transmission from base station 102,112.When this travelling carriage determines that second base station 112 provides good quality (according to threshold value), through these cdma base station controller (CBSC) 114 informing base stations 102,112.Communication from first base station 102 to travelling carriage 106 is terminated, and the responsibility of communication is shouldered in second base station 112.Why this switching of district excessively is known as ＂ soft handover ＂ because of the viewpoint from travelling carriage 106 communication interruption does not take place.
When entering of soft handover is delayed (because service selection change/mistake is distinguished the very long combination of handoff procedure), travelling carriage 106 will be increased with the threshold value of this initial soft handover.The increase of this threshold value has caused the higher relatively power demand amount that will be sent by travelling carriage 106.Because in any communication system, the power of transmission is high more, and the interference that communication system stands is just big more.In cdma communication system, the increase of system interference has caused reducing of power system capacity, or the minimizing of the quantity of the travelling carriage 106 that can be served by arbitrary base station 102,112.
Fig. 2 briefly illustrates the transmitter 200 that helps implementing the travelling carriage 106 of receiver 203 in cdma communication of mode of the present invention and base station 102 with a kind of.In the coded portion 201 of this communication system, traffic channel data bit 202 starts from microprocessor (μ P) 205, and (for example, 9.6Kb/s) is input to encoder 204 with a specific bit rate.This μ P205 has been connected to the square frame 207 of corresponding function designated, the function of this square frame comprise call treatment, link establishment with set up and keep other relevant general utility functions of cellular communication.Traffic channel data bit 202 can comprise speech, the clear data that is converted to data by vocoder, or the combination of these two kinds of data.Encoder 204 utilization be convenient to the continuous maximum-likelihood decoding of data symbols become data bit encryption algorithm (for example, convolution or block encoding algorithm) with a regular coding speed (1/r) traffic channel data bit 202 is encoded into data symbols 206.For example, encoder 204 with a data bit to the regular coding speed of three data code elements (promptly, 1/3) to traffic channel data bit 202 (for example, 192 data bits that receive with the speed of 9.6Kb/s) encode, so that these encoder 204 dateout code elements 206 (for example, 576 data code elements exporting with the speed of 28.8 thousand code elements/s).
Data symbols 206 is imported into interleaver 208 then.Interleaver 208 is formed data symbols 206 a plurality of (that is frames) and with this symbol level data code element 206 is carried out piece and interlocks.In interleaver 208, data symbols is input to a matrix that defines the predetermined length piece of data symbols seriatim.Data symbols is imported into each position in this matrix, so that in the mode by row this matrix is full of.Data symbols is exported one by one by each position in matrix, so that this matrix is soared in mode line by line.Typically, this matrix is the square matrix that a line number equates with columns; Yet, also can choose other matrix form, with the staggered distance of the output between the noninterlace data symbols that increases continuous input.Identical data symbols speed (for example, 28.8Kb/s) output when being transfused to it by interleaver 208 by intercrossed data code element 110.The predetermined length of the data symbol blocks that is limited by described matrix is by obtaining in the maximum data number of symbols that can send with encoding bit rate in the transmission piece of a predetermined length.For example, if data symbols 206 is exported from encoder 204 with the speed of 28.8Kb/s, if and the predetermined length that sends piece is 20 milliseconds, then the predetermined length of this data symbol blocks is that 28.8Kb/s multiply by 20 milliseconds (ms), equals to define 576 data code elements of one 18 * 32 matrix.
Coding, staggered data symbols 210 are exported from the coded portion 201 of communication system, and are imported into the transmission part 216 of communication system.Data symbols 210 is prepared through communication channel and is sent by modulator 217.Subsequently, this modulated signal is provided for antenna 218, so that send through digital radio channel 108.
In expansion process, modulator 217 is ready to data symbols 210 by derive a fixed-length code sequence from the data symbols 210 that is encoded, interlocks for direct sequence sign indicating number branch spread spectrum transmission.For example, the data symbols in baseline encoded stream of data symbols 210 can be extended to the fixed-length code of a uniqueness, so that with one 6 numeric data code tuple of single 64 bit length representation.The sign indicating number of representing this 6 numeric data code tuple is combined to form single 64 bit length sign indicating numbers.Because the result of this expansion process, with a fixed rate (for example, 28.8Kb/s) receive that this is encoded, the modulator 217 of staggered data symbols 210 has (for example, the sequence spreading of 64 bit length sign indicating numbers 307.2Kb/s) that has higher fixedly chip rate now.One skilled in the art will appreciate that according to many other algorithms, be encoded, the data symbols in the staggered stream of data symbols 210 can be extended to a more sequence of length sign indicating number, and do not depart from the scope of the present invention and spirit.
Utilize a long spreading code (for example, the PN sign indicating number) that described sequence spreading is further expanded, this sequence spreading is further prepared direct sequence sign indicating number branch spread spectrum transmission.This extended code is the specific sequence of symhols of user or with the user code of a uniqueness of a stator speed (for example, 1.228 million slices/second) output.Except providing which user to send through digital radio channel 108 sign of the traffic channel data bit 202 that is encoded, this unique user code is by the scramble communications security that traffic channel data bit 202 strengthens in the communication channels that is encoded.In addition, this user code extended coding data bit (that is, data symbols) is used to by driving the phase control to a sine wave, so that this sine wave is carried out bi-phase modulated.This sine wave signal output is converted to the RF frequency by bandpass filtering, is exaggerated, filtering and by antenna 218 radiation, finishes the transmission of the traffic channel data bit 202 in digital radio channel 108 by binary phase shift keying (BPSK) modulation.
The receiving unit 222 of base station receiver 203 receives the spread-spectrum signal that is sent out by antenna 224 through digital radio channel 108.The signal that receives is taken a sample into data sample by despreader with sampler 226.Subsequently, this data sample 242 outputs to the decoded portion 254 of communication system.
Despreader and sampler 226 are preferably by filtering, demodulation, carry out the BPSK sampling from the conversion of RF frequency with set rate (for example, 1.228 million sample value/seconds) sampling to the spread-spectrum signal that receives.Subsequently, relevant by the sampled signal that makes reception with described long spreading code, the signal of being taken a sample by BPSK is carried out despreading.The despreading sampled signal 228 that obtains with set rate sampling, and it (is for example outputed to non-coherent detector 240,307.2K sampling/second, so that 4 sample value sequences of the spread spectrum spectrum signal that receives are represented by despreading and/or by the individual data sample value), be used for the incoherent detection 242 of later data sample.
Will be appreciated that as those skilled in the art a plurality of receiving units 222 to 223 and antenna 224 to 225 can be used for the implementation space diversity reception respectively.Aforesaid receiving unit 222, a N receiver section will be worked in essentially identical mode, and the spread spectrum spectrum signal that receives from digital radio channel 108 recovers each data sample.The output 242 to 252 of N receiving unit preferably is input to summer 250, and this summer 250 is combined into the combined-flow 260 that coherently detects data sample to the data sample branch of input.
Each data sample 260 that forms soft-decision data is imported into decoded portion 254 then, and this decoded portion 254 comprises " deinterleave " device 262 that input soft-decision data 260 is carried out " deinterleave " by each data level.In " deinterleave " device 262, this soft-decision data 260 is input to a matrix that defines the predetermined length of soft-decision data piece one by one.This soft-decision data is imported into each position in this matrix, so that in mode line by line this matrix is full of.The soft-decision data 264 of deinterleave is exported one by one from each position in this matrix, so that make this matrix to soar by the mode of row.The data symbols 264 of " deinterleave " identical speed (for example, 28.8kilometrics/s) output when being transfused to it by " deinterleave " device 262.
Try to achieve by the maximum rate that the predetermined length of the soft-decision data piece that this matrix limited is taken a sample to the data sample value by the spread spectrum spectrum signal that receives in the predetermined length transmission block.
The soft-decision data 264 of " deinterleave " is imported into a decoder 266, and this decoder 266 uses the maximum likelihood decoding technology to produce the traffic channel data bit of estimating 268.The maximum likelihood decoding technology can be increased by using identical with Viterbi (Viterbi) decoding algorithm basically algorithm.Decoder 266 uses one group of independent soft-decision data 264 to form a soft-decision conversion degree duration set, uses for each the special time state at this maximum likelihood sequence estimation decoding device 266.The quantity that is used for forming the soft-decision data 264 in described group of each soft-decision conversion degree duration set is corresponding with the quantity of the data symbols 206 of the output of the convolution coder 204 that produces at each input data bit 202.The n power that the quantity of soft-decision conversion tolerance equals 2 in each set, n is the quantity of soft-decision data 264 in every group.For example, when in transmitter, using one 1/3 convolution coder, from each input data bit 202, produce three data code elements 106.Like this, decoder 266 utilizes three independent soft-decision data of array 264 to constitute 8 soft-decision conversion amounts, uses at each time state for maximum likelihood sequence estimation decoding device 266.Be imported into the speed of decoder 266 and be used for that input data bit 202 is carried out the relevant speed of the fixed rate of initial code with soft-decision data 264 with one and (for example produce by estimation traffic channel data bit 268, if this soft-decision data is to import for 28.8 thousand tolerance/seconds, with initial code speed be 1/3, then this quilt estimates that traffic channel data bit 268 will be with 9600 bps speed output).
Estimated that traffic channel data bit 268 is imported into the similar μ P270 with μ P207.As the situation at μ P207, this μ P270 is coupled to the square frame 272 of having specified corresponding function, and this square frame is also carried out and comprised call treatment, link establishment with the function of setting up other general utility functions relevant with keeping cellular communication.μ P270 is also connected to an interface 274, and it allows the receiver 203 of base station 102 to communicate with CBSC 114.
Fig. 3 briefly illustrate a kind of with help implementing mode of the present invention with the transmitter 300 of base station 102 during the receiver 303CDMA of a travelling carriage 106 communicates by letter.In the coded portion 301 of this communication system, traffic channel data bit 302 is exported from μ P305, and is imported into encoder 304 with a specific bit rate (for example, 9600 kilobits/second).This μ P305 is connected to the square frame 307 of having specified corresponding function, and this square frame is carried out square frame 207 and the 272 similar cellular communication function associated with Fig. 2.μ P305 is also connected to an interface 309, and it allows the transmitter 300 of base station 102 to communicate with CBSC 114.
Traffic channel data bit 302 can comprise speech, the clear data that is converted to data by vocoder, or the combination of these two kinds of data.Encoder 304 utilization is convenient to the encryption algorithm (for example, convolution or block encoding algorithm) that continuous maximum-likelihood decoding data symbols is decoded into data bit and with a regular coding speed (1/r) traffic channel data bit 302 is encoded into data symbols 306.For example, encoder 304 with a data bit to the regular coding speed of two data code elements (promptly, 1/2) to traffic channel data bit 302 (for example, 192 data bits that receive with the speed of 9.6Kb/s) encode, so that these encoder 304 dateout code elements 306 (for example, 384 data code elements exporting with the speed of 19.2 thousand code elements/s).
The data symbols 310 that is encoded, interlocks is exported from the coded portion 301 of communication system, and is imported into the transmission part 316 of communication system.Data symbols 310 is prepared through communication channel and is sent by modulator 317.Subsequently, this modulated signal is provided for antenna 318, so that send through digital radio channel 108.
By with a long spreading code (for example, the PN sign indicating number) described sequence spreading being further expanded, this sequence spreading is further got ready for the direct sequence sign indicating number divides the transmission of spread spectrum spectrum.Described extended code is the specific sequence of symhols of user or with the user code of the uniqueness of stator speed (for example, 1.228 million slices/second) output.Except providing which user through digital radio channel 308 has sent the sign of the traffic channel data 302 that is encoded, this unique user code strengthens the fail safe of communicating by letter in the communication channels by the scramble traffic channel data 302 that is encoded.In addition, expanding the data bit (that is data symbols) that is encoded by this user code of phase control that drives sine wave is used to this sine wave is carried out bi-phase modulated.This sine wave signal output is converted to the RF frequency by bandpass filtering, is exaggerated, filtering and by antenna 318 radiation, finishes the transmission of the traffic channel data bit 302 in digital radio channel 108 by the BPSK modulation.
The receiving unit 322 of mobile station receiver 303 receives the spread spectrum spectrum signal that is sent out by antenna 324 through digital radio channel 108.Received signals is taken a sample into data sample by despreader with sampler 326.Subsequently, this data sample 342 is output to the decoded portion 354 of communication system.
Despreader and sample value device 326 are preferably by filtering, demodulation, carry out the BPSK sample value from the conversion of RF frequency with set rate (for example, 1.228 million sample value/seconds) sample value to being received spread-spectrum signal.Subsequently, relevant by the sampled signal that makes reception with described long spreading code, the signal of despreading BPSK sampling.With a set rate despreading sampled signal 328 that obtains is taken a sample, and it (is for example outputed to non-coherent detector 340,19.2K sample value/second, so that receiving 64 sample value sequences of spread spectrum spectrum signal represents by despreading and/or by the individual data sample value), be used for the incoherent detection 342 of data sample.
Will be appreciated that as those skilled in the art a plurality of receiving units 322 to 323 and antenna 324 to 325 can be used for the implementation space diversity respectively.Aforesaid receiving unit 322, a N receiver section will be worked in essentially identical mode, recover each data sample the spread spectrum spectrum signal from being received of digital radio channel 320.The output 342 to 352 of N receiving unit is imported into summer 350, and this summer 350 is combined into a combined-flow 360 that coherently detects data sample to the data sample diversity of input.
Each data sample 360 that forms soft-decision data is imported into decoded portion 354 then, and this decoded portion 354 comprises " deinterleaver " 362 that input soft-decision data 360 is carried out " deinterleave " by each data level.In " deinterleave " device 362, this soft-decision data 360 one by one is input to the matrix of the preliminary dimension that limits the soft-decision data piece.This soft-decision data is imported into each position in this matrix, so that in mode line by line this matrix is full of.The soft-decision data 364 of " deinterleave " is exported one by one from each position in this matrix, so that make this matrix to soar by the mode of row.The identical speed that the soft-decision data 364 of " deinterleave " is transfused to them by " deinterleave " device 362 (for example, 19.2k tolerance/s) output.
Try to achieve the maximum rate of pre-sizing by the soft-decision data piece that this matrix limited by the sampled data sample value of the spread spectrum spectrum signal that in the predetermined length transmission block, receives.
The soft-decision data 364 of " deinterleave " is imported into a decoder 366, and this decoder 366 uses the maximum likelihood decoding technology to produce by estimation traffic channel data bit 368.The maximum likelihood decoding technology can use identical with Viterbi (Viterbi) decoding algorithm basically algorithm to be increased.Decoder 366 uses one group of independent soft-decision data 364 to form a soft-decision conversion degree duration set, uses for each the special time state at this maximum likelihood sequence estimation decoding device 366.Be used for forming the quantity of the quantity of the soft-decision data 364 in described group of each soft-decision conversion value set corresponding to the data symbols 306 of the output of the convolution coder 304 that produces from each input data bit 302.The n power that the quantity of soft-decision conversion tolerance equals 2 in each set, n is the quantity of soft-decision data 364 in every group.For example, when in transmitter, using one 1/2 convolution coder, from each input data bit 302, produce two data code elements 306.Like this, decoder 366 utilizes two independent soft-decision data 364 of array to constitute 4 soft-decision conversion tolerance, uses at each time state for maximum likelihood sequence estimation decoding device 366.(for example produce to be imported into the speed of decoder 366 with soft-decision data 364 and to be used for that input data bit 302 is carried out the relevant speed of the fixed rate of initial code by estimation traffic channel data bit 368, if this soft-decision data is 1/2 with 19.2k tolerance/s input and initial code speed, then this quilt estimation traffic channel data bit 368 will be exported with 9600 bps speed).By estimate traffic channel data bit 368 be imported into this μ P370 translation of a μ P370. estimate traffic channel data bit 368 and in digital radio channel 108, send expanded the field of distinguishing hand off direction message ＂ such as ＂.This μ P370 is connected to function corresponding square frame 372, and this square frame is carried out the similar and cellular communication function associated of carrying out with square frame 207,272 and 307.
Fig. 4 briefly illustrates the protocol hierarchy structure that is used for cdma communication system.As shown in Figure 4, this agreement logically is divided into notional layer.Layer 1400, or the physical layer of digital radio channel 108 comprises those functions relevant with bit transfer.These functions comprise modulation, coding, framing and through the radio wave channelizing.Multiplex sublayer 402 provides the multiplexed function that allows user data and signaling process to share digital radio channel 108.Signaling protocol layer 2 is subdivided into an elementary operation layer 2 404 and a second level operation layer 2 406 again, and be and between base station 102 and travelling carriage 106, (for example carry out the signaling higher-layer messages, from last layer 408,410) the relevant agreement of reliable transmission.Such top signaling message comprises message retransmission and duplicate detection.
As previously mentioned, the service selection of IS-95A is limited by TSB58, and the current basic variable bit rate voice service (8kps) that comprises, the travelling carriage loopback, the variable bit rate voice service (8kps) of enhancing, asynchronous data traffic, the Group-3 fax business, short message service, transmission control protocol/internet protocol packet data business and the Cellular Digital Packet Data (CDPD) on point-to-point (PPP) Packet data service.Institute's protocols having in multiplexed sublayer more than 402 is that service selection is irrelevant.In other words, 102 signalings that change service selection to travelling carriage 106 are at layer 2 404 from the base station, 406 or carry out with the upper strata.
Another parameter that is sent to travelling carriage 106 by base station 102 is the parameter that is known as rate setting (rate set), and this parameter is used to be defined in the data rate that uses on the digital radio channel 108.IS-95A is two rate setting parameters of definition at present, and rate setting 1 and rate setting 2, each rate setting all have its service selection group.Because changing, rate setting can change digital radio channel 108 (by changing acoustic coding rate through this channel, thereby also changed the bandwidth of this channel), so rate setting changes for layer 1 400, the physical layer of promptly supporting digital wireless channel 108 is opaque.Yet,, just can change service selection, and need not to change physical layer in case this rate setting parameter is set.In other words, change for layer 1 400 for any service selection of a given rate setting, the physical layer of promptly supporting digital wireless channel 108 is transparent.
As previously mentioned, according to the present invention, the service selection in code division multiple access (CDMA) communication system 100 is by at first determining and will being changed by the service selection of these travelling carriage 106 uses and the data that are pre-stored in expression service selection in the message to these travelling carriage 106 transmissions in travelling carriage 106.In this preferred embodiment, the data of expression service selection are 16 bit fields of one of a plurality of service selection of expression, and being pre-stored in message is that a ＂ enlarged district hand off direction message ＂.Fig. 5 illustrates one and crosses district's switching message, and the ＂ that particularly wherein has the data that related to district's switching and service selection data representation according to the present invention enlarged district hand off direction message ＂ 500.As shown in Figure 5, message 500 has a ＂ added field ＂ field 502, and it is retained by base station/travelling carriage producer and uses as required, and is 16 bit long.In a preferred embodiment of the invention, the field 502 in the message 500 comprises 16 bit service selection data representations, is used for changing service selection at travelling carriage.Because the change in the service selection occurs in layer 2 and with upper strata (as seeing among Fig. 4), so both can comprise can also can be in second level operation layer 2 406 service selection of (as by data field 506 expressions) at elementary operation layer 2404 (as by data field 504 expressions) for ＂ added field ＂ field 502.
Some time division multiple access (TDMA) communication system, the Digital Cellular System (global system that is used for mobile communication such as Europe, be GSM) and Japanese Digital Cellular System (personal digital cellular, be PDC) used one to cross district's switching message, to change some layer 1 feature: the feature that promptly relates to digital radio channel 108.Yet, as mentioned above, be at layer 2 404 because change all relevant signalings with service selection, 406 or more high-rise go up to carry out, so for a given rate setting, it is fully transparent that the service selection in a cdma communication system changes for digital radio channel 108.
With reference to figure 1, the following exemplary that in travelling carriage, how can change service selection that provides.Suppose that travelling carriage 106 is positioned at first overlay area 104 and communicates by letter with first base station 102 of supporting first group of service selection, and entering second overlay area 110 by second base station, 112 services of supporting second group of service selection, first base station 102 is at first discerned honeycomb to cross that the district switches is necessary then.Although service selection needs,, it is necessary for allowing travelling carriage 106 to keep from the communication of 104 to second overlay areas 110, first overlay area that honeycomb is crossed district's switching.
This time because first base station 102 knows that it is essential that honeycomb crosses that the district switches, so first base station 102 also can be determined the service selection that will use and check whether second base station 112 supports determined service selection.This step is essential, because second base station 112 may be the base station of having selected to support the different operators that different business is selected.Will be clearly as those of ordinary skill in the art, available service selects information can reside among first base station 102 or the CBSC 114.Subsequently, according to determining, first base station 102 will be inserted into ＂ to the data representation that is determined service selection and enlarge in the ＂ added field ＂ field 502 of distinguishing hand off direction message ＂ 500 and will enlarge district hand off direction message ＂ 500 to this ＂ and send to travelling carriage 106.Travelling carriage 106 will receive this ＂ and enlarge district hand off direction message ＂ 500, and the data in this message are delivered to μ P370 so that translation.μ P370 translates the data that receive, and changes described service selection and changes the receiver 303 of travelling carriage 106 according to the data representation in the ＂ added field ＂ field 502, crosses the district and switches so that carry out honeycomb according to the present invention.
Will clearly change the district of crossing that is not limited between aforesaid mesh according to service selection of the present invention and switch as those of ordinary skill in the art.For example, change the switching that can advantageously be applied in the mesh according to service selection of the present invention.With reference to figure 1, owing to all restrictions to this system, travelling carriage 106 can require the switching in the mesh.As an example, capacity limit may limit the service selection of being supported by a given base station 102.In each time of high power system capacity (one day among rush hour), can design base station 102 and not support some time-consuming channel service to select, such as the Group-3 fax machine.When power system capacity reduced (one day off-peak hours), then base station 102 allowed all service selection of being supported.These system constraint can be that transparent way provides to the digital radio channel 108 by the agreement support of layer 1 400.
Do not carry out the negotiations process of the trouble of prior art because do not need extra time, so the increase of call dropping rates can not occur according to cdma communication system execution service selection change according to the present invention.In addition, because all signalings all occur in layer 2 404,406 or more high-rise, be transparent so change digital radio channel 108 by the agreement support of layer 1 400 according to service selection according to the present invention.At last, when comparing with the method that the service selection of prior art changes, because travelling carriage 106 can not postpone in entering the softer handoff switching, so reduced system interference, this has caused the corresponding increase of power system capacity.
Though show especially and describe that with reference to specific embodiment the present invention those skilled in the art will be appreciated that, can make various changes in form and details, and can not break away from the spirit and scope of the present invention.
Claims (10)
1. method that changes service selection in code division multiple access (CDMA) communication system is characterized in that this method may further comprise the steps:
Determine the service selection that travelling carriage will use; With
Be sent in data that are pre-stored in this service selection of expression in the message to this travelling carriage.
2. according to the method for claim 1, it is characterized in that the data of described this service selection of expression also comprise 16 bit fields of one of a plurality of service selection of expression.
3. according to the method for claim 1, it is characterized in that the described message that is pre-stored in comprises that also crossing the district for one switches message.
4. according to the method for claim 1, it is characterized in that it is transparent being sent in the physical layer that a step that is pre-stored in the message data of the described service selection of expression takes place for this forwarding step thereon.
5. method that in travelling carriage, changes service selection, the base station communication of this travelling carriage and a cdma communication system is characterized in that, this method may further comprise the steps:
The data of crossing the service selection of indicating to use district's switching message that reception sends from described base station; With
Change in service selection described in the travelling carriage according to cross the data that receive in district's switching message at this.
6. according to the method for claim 5, it is characterized in that the step that changes described service selection is transparent for sending this physical resource of crossing district's switching message thereon.
7. method that in travelling carriage, changes service selection, this travelling carriage is compatible mutually with a cdma communication system, this travelling carriage and first base station communication and requirement are crossed the district and are switched to one second base station from first base station, the current business that this travelling carriage is implemented to be supported by first base station is selected, it is characterized in that, said method comprising the steps of: in first base station:
The definite service selection that will use by second base station;
The data representation of the service selection of determining is inserted into one to be crossed in district's switching message; With
When requiring the district to switch, should cross district's switching message and send to described travelling carriage; At described travelling carriage:
Receive the described district of crossing from first base station and switch message;
Change described service selection according to described data representation; With
According to the described district's switching message of crossing communication is changed to second base station from first base station.
8. according to the method for claim 7, it is characterized in that soft handover is supported in first base station of this cdma communication system and second base station.
9. travelling carriage of supporting a plurality of service selection, this travelling carriage and code division multiple access (CDMA) communication system be compatibility mutually, it is characterized in that this travelling carriage comprises:
A receiver is used for receiving distinguishing and switches message, and this crosses the data that district's switching message comprises the data representation of service selection and relates to the district's switching of communicating by letter; With
A microprocessor is used to translate described the mistake and distinguishes switching message, so that implement and the corresponding service selection of described data representation, changes the receiver of this travelling carriage to carry out the described district's switching of communicating by letter with being used to.
10. according to the travelling carriage of claim 9, it is characterized in that, described cross the district switch message be cross between relevant mesh that the district switches or mesh in cross the district of crossing of switching in the district and switch message.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96190568 CN1154778A (en) | 1995-06-08 | 1996-04-17 | Changing a service option in a CDMA communication system |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/488,668 | 1995-06-08 | ||
| CN 96190568 CN1154778A (en) | 1995-06-08 | 1996-04-17 | Changing a service option in a CDMA communication system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1154778A true CN1154778A (en) | 1997-07-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 96190568 Pending CN1154778A (en) | 1995-06-08 | 1996-04-17 | Changing a service option in a CDMA communication system |
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| Country | Link |
|---|---|
| CN (1) | CN1154778A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1053313C (en) * | 1997-04-21 | 2000-06-07 | 北京信威通信技术有限公司 | Time division duplex synchronous code partition multi-address radio communication system |
| CN100387095C (en) * | 2004-09-24 | 2008-05-07 | 华为技术有限公司 | Method of realizing business type change |
| CN101674618A (en) * | 2002-09-24 | 2010-03-17 | 富士通株式会社 | Packet transmission/delivery method and mobile communication system |
| CN101064727B (en) * | 2006-04-30 | 2010-06-23 | 中兴通讯股份有限公司 | Process method for realizing packet based bear format negotiation in C network |
| CN101124830B (en) * | 2002-12-06 | 2011-07-20 | 摩托罗拉移动公司 | Method and apparatus for improving hard handoffs in CDMA systems |
-
1996
- 1996-04-17 CN CN 96190568 patent/CN1154778A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1053313C (en) * | 1997-04-21 | 2000-06-07 | 北京信威通信技术有限公司 | Time division duplex synchronous code partition multi-address radio communication system |
| CN101674618A (en) * | 2002-09-24 | 2010-03-17 | 富士通株式会社 | Packet transmission/delivery method and mobile communication system |
| CN101124830B (en) * | 2002-12-06 | 2011-07-20 | 摩托罗拉移动公司 | Method and apparatus for improving hard handoffs in CDMA systems |
| CN100387095C (en) * | 2004-09-24 | 2008-05-07 | 华为技术有限公司 | Method of realizing business type change |
| CN101064727B (en) * | 2006-04-30 | 2010-06-23 | 中兴通讯股份有限公司 | Process method for realizing packet based bear format negotiation in C network |
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