Describe in detail
With reference to specific configuration several exemplary embodiment are described.One of skill in the art will appreciate that within the scope of the claims and can make various changes and modification.For example, exemplary embodiment adopts GSM standard, but any TDMA, FDMA, the standard of CDMA or other types all may be utilized.A. network configuration
Fig. 1 describes a kind of Cellular Networks structure according to embodiment of the present invention.Mobile switching centre (MSC) 102 is linked a public switch telephone network (PSTN) 104.MSC has one to be configured to the interface of communicating by letter with PSTN, so that from the PSTN receipt of call and transfer them to mobile radio station and from the mobile radio station receipt of call and transfer them to PSTN.MSC is the part of a private network, and this net comprises base station controller (BSC) 106a-106c, concentrated basic transceiver station (CBTS) 108a-108f and remote transmitter-receiver (RTRX) 110a-110r.Private network also comprises an operation and maintenance centre (OMC) 112.The 2nd MSC114 also is shown, BSC116, CTBS118 and RTRX120a-120c.These network componentses are below described in more detail.
The net of Fig. 1 has several tangible benefits.At first, the honeycomb covering can be by customized on request by placing RTRX easily.Because each RTRX represents a Microcell, RTRX can be placed in can more easily cover by cellular communication and wish in the zone of the whole area that covers.Secondly, because RTRX represents the minimum relatively hardware of a cover, they are comparatively cheap.Therefore, the cost of deployment is low, and the construction of whole system and installation are comparatively cheap.The 3rd, because RTRX communicates by letter with CBTS on coaxial or optical cable, they can be placed on the required open air of antenna, this just reduces the electronic unit that is subjected to the weather elements affect easily and allows more expensive CBTS electronic unit to be installed in the shell that prevents weather effect, a building can being controlled more exactly as temperature.These three benefits, and other advantage make the present invention attractive to the technical unit designer, owing to improve the flexibility that the design honeycomb covers; Attractive to mounting technique person, he can be placed on the heavy equipment with expensive in the building together, and extend coaxial or optical cable to the outside, less RTRX is placed on their positions separately; With attractive to financial management person, he can reduce the deployment of total cost and lower relevant maintenance and repair Cost Management System.
1)OMC
With reference to figure 2, OMC112 is configured to the supervising connections for calling management.OMC comprises the network interface (NIF) 202 with special-purpose cellular network communication.Central processing unit (CPU) 204 be used to handle from the information of Cellular Networks and with other partial interactions of OMC.Network topology memory 206 is linked CPU and is used to recover the topological structure of Cellular Networks by CPU.Frequency meter memory 208 is linked CPU and is used to keep on demand information about the mobile radio station frequency.User interface 210 is provided to receive from technician's information and provides information to the technician.OMC is configured to the supervising connections for calling management and the report situation is given user interface 210.The management function of OMC comprises network management, configuration management, alarm and incident management, user management and test and diagnosis management.The OMC Network management function comprises the inspection fault state, carries out fault and shifts, and transmits extra communication service by projected route, writes down and avoid interference situation, carries out test and maintenance program and monitoring user storehouse and other situation.Below describe these functions in greater detail.
2) MSC and BSC
MSC has the ability to transmit call, from PSTN to the private network, from the private network to PSTN and in private network.Private network comprises the BSC that communicates by letter with MSC and control independent basic transceiver station (BTS).BTS in exemplary embodiment comprises concentrated basic transceiver station (CBTS) and remote transmitter-receiver (RTRX).The detailed explanation of CBTS and RTRX is described in the U.S.Ser.No.08/914 that submitted on August 20th, 1997, in 982 and be introduced in that this is for reference.
Communication between A interface realization BSC and MSC.In one embodiment, the physical transfer media is a cable, communication service data, and radio control signal and state are utilized a kind of digital baseband physical layer protocol (T1, E1, E2, E3, DS1, DS3, etc.), transmit between BSC and MSC by the ATM(Asynchronous Transfer Mode) link.Another kind of can the selection or other scheme can be adopted Internet Protocol (IP) communication technology.
With reference to figure 3, MSC106 is configured to the calling that networks and go out net with PSTN by common interface 250.The detailed explanation of transfer capability is described in U.S.Pat.No.5, in 734,979, is introduced in that this is for reference.CPU (CPU) 252 is connected to the VME bus 254a from common interface 250 receiving communication signals.CPU252 is also linked TDM bus 254b.CPU serves many purposes, comprises control common interface 250 and trunk module 256, or is called as the inbound communication between the special purpose interface and the transmission of outbound information sometimes.Trunk module has an E1 interface, is used for and remaining private network (VPN) communication.Such interface is known technically, and can be replaced by T1, DSO or other interface.MSC comprises master site register (HLR) 258 and visitor location register (VLR) 260.These register-stored are look to tracking mobile station and confirm their information during initialization.MSC comprises routing table 262, makes MSC communication frequency can be distributed to mobile radio station and RTRX, so that reduce interference and promote the multiplexing of frequency.The algorithm of this this type is known technically, below describes some novel part of the present invention in detail.MSC comprises the network topology memory, makes MSC can discern each BSC, CBTS, and RTRX and other network components, network topological information provides MSC a basis, and communication frequency can be assigned to mobile radio station in view of the above, can realize that in view of the above maximum honeycomb covers.
Fig. 4 describes CPU 252 in detail.A VME interface 302 is linked VME bus 254a.Interface 302 is linked in redundancy control 304, in order to monitoring interface 302 and if necessary just take over.Processor 306 is linked interface 302 so that communicate by letter on VME bus 254a.When calling was issued, processor 306 received grouping information from mobile radio station.The signal path of processor 306 controlling call also disposes trunk module 256, makes to be adapted to call out exchange.In addition, processor 306 is fulfiled the function that many internal affairs required in MSC are handled and dispatched, as safeguards existing record with mobile radio station, and their information rate is called out link information and other information.Clock is regulated 308 and is received the clock signal and utilize other trace information to proofread and correct this signal, in full reportedly send clock, makes this clock and unified conformance to standard.CPU252 also has the various DRAM310 that mouthful are used to resemble, the module that flash memory 312 is such, and one standby mouthful 314 is used for IDE, SCSI or RS232 and Ethernet 316.
Described below some dispose several CPU.The benefit of additional CPU comprises redundancy, flexibility and the central disposal ability of increase.When MSC was linked several other network components, in order to coordinate to network and go out net information, by control trunk module 256 exchanges of the following stated, disposal ability was useful.
Fig. 5 A-B describes trunk module 256.Heart at trunk module is time/space switching 402, has both linked the TDM bus 254b that is used for data, links the VME bus 254a that is used to control again.Time/space switching 402 can be in the TDM bus, processor 404, interface framer 410, and transmission information between the DSP 420a-420f.According to its communication data rate and switching capability time/space switching 402 is described at this.Any equipment that can fulfil these functions can be used among the present invention, and as the digital switch IC family of 3c Ltd.C3280 processor or Siemens, wherein PEB2045 memory clock switch is an example.
Time/space switching 402 has many mouthfuls, as shown in Fig. 5 B.All 16 TDM branch buses are linked in a PCM input port, and each can transmit 8Mbps.In fact, time/space switching 402 can with maximum 16 module communications, as TRX, other trunk module, or attach to the module of any other type of TDM bus.If time/space switching 402 is configured with more mouth and the TDM bus is configured with more minute bus, then bigger quantity is possible.
Time/space switching 402 is supported in U.S.Pat.Nos.5, and many switching functions of describing in 734,699 and 5,577,029 are introduced in this as a reference.And when the base station was configured to fulfil switching function, honeycomb PBX can be fulfiled in the base station, the function of home loop, or other similar functions.
Processor 404 is linked time/space switching 402 by 8Mbps CPU360Y and CPU360Z input port, and further links 8Mbps path Y and path Z delivery outlet, as shown.Processor 404 is also linked the VME bus, as shown in Fig. 5 A.Processor 404 is provided the realization protocol processes.Possible agreement comprises Abis, A, SS#7, ISDN and other.This processing makes can cooperation ground inter-working between the miscellaneous part of GSM net and PSTN.And processor 404 provides the distributed treatment to trunk module 256 special uses, and along with the increase of the number of trunk module is carried out in proportion.Processor 404 also provides service as a kind of protocol engine for trunk module 256, helps to reduce stand-by period and the performance of improving for treatment S S#7 signal.If do not need protocol processes, CPU 252 appears in the configuration, and processor 404 can be omitted, because CPU 252 comprises the processor 306 that is used to realize general utility functions.
DSP 420a-420f is linked time/space switching by 8Mbps path Y and path Z delivery outlet.When echo is eliminated, rate adapted, or certain other functions are when being required, and time/space switching 402 is sent to DSP420 with information and handles.As shown, 6 DSP420a-420f are arranged, yet, by handle required they can be to any number from zero.Which DSP420a-420f is a kind of selection control storage 418 what information of control be sent to.In case DSP420a-420f finishes their functions separately, information is transmitted back to time/space switching 420 by the input port by path Y and path Z.DSP420a-420f can be a processor, as AT﹠amp; T DSP1611, TI TMS 320c52, or similar product.
For describing the function of TRAU, for example, because a GSM mobile radio station transmits the speech 16kps that has compressed, and the PSTNDSO interface is 64kbps.DSP420 revises compression and changes to adapt to this speed.DSP420 also can adapt to any speed such as 8kbps, 16kbps, and the speed between the 64kbps etc. changes.
The second aspect of the present embodiment is tangible, when the calling from first mobile radio station 111a second mobile radio station 111b in the network service area territory was done, time/space switching 402 can turn back to TDM bus from first mobile radio station as the outbound information for the second mobile radio station 111b with inbound communication simply.Such switch is explained in U.S.Pat.Nos.5, and 734,979; In 5,734,699 and 5,577,029, be introduced in this as a reference.
The call route selecting function also can be various additive method realize that this depends on communicating by letter of mobile radio station and network.For example, if the first mobile radio station 111a and the second mobile radio station 111b communicate by letter with single RTRX 110b, RTRX can send to second mobile radio station with it as outbound information then from the first mobile radio station reception of inbound data.Because still being outbound information, inbound communication all is in 13.2kbps, and inbound and departures in single RTRX, so do not need to be packaged as the data flow of 16kbps.As second example, if the first mobile radio station 111a and the second mobile radio station 111b respectively with different RTRX, communicate by letter with 110b as 110a, but carry out with identical CBTS108a, the one RTRX110a is from the first mobile radio station 111a reception of inbound data, transmit information by CBTS108a then, and with it as sending for the outbound information of the 2nd RTRX110b, send to the second mobile radio station 111b then, because inbound and outbound information are handled by different RTRX, this information is packaged as the 16kbps data flow and communicates by letter with CBTS108a.As the 3rd example, if the first mobile radio station 111a communicates by letter with a RTRX110a relevant with a CBTS108a, the second mobile radio station 110b communicates by letter with the 2nd RTRX110e relevant with the 2nd CBTS108b, the one RTRX reception of inbound information also sends to the 2nd CBTS108b by CBTS108a and BSC106a with it, with it as the outbound information of the 2nd RTRX110e and the second mobile radio station 111b is treated.Because inbound and outbound information are handled by different RTRX, this information is packaged into the 16kbps data flow and communicates by letter between RTRX.As the 4th example, if the first mobile radio station 111a communicates by letter with a RTRX110a relevant with a CBTS108a and a BSC106a, the second mobile radio station 110b communicates by letter with the 2nd RTRX110h relevant with the 2nd CBTS108c and the 2nd BSC106b, the one RTRX reception of inbound information is also passed through CBTS108a, BSC106a and BSC106b send to the 2nd CBTS108c with it, and it is handled as the outbound information to the 2nd RTRX110h and the second mobile radio station 111b.Because inbound and outbound information are handled by different RTRX, this information is packaged into the 16kbps data flow and communicates by letter between RTRX.Notice that these examples do not send information to MSC102, notice that these examples are not 64kbps with the information decompress(ion) yet.
3) CBTS and RTRX
According to one aspect of the present invention, provide a kind of CBTS structure at this, wherein transmitter-receiver (TRX) is divided into two subsystems: with CBTS center TRX (CTRX) subsystem and geographical remote TRX (RTRX) subsystem that goes up away from CBTS and CTRX together.This respect of the present invention is described in the U.S.Ser.No.08/917 that submitted on August 20th, 1997, in 982, is introduced in this as a reference.According to this respect of the present invention, RTRX comprises the RF antenna circuit, is used to utilize mobile radio station to pass through the RF signal and sends outbound information and reception of inbound information.Outbound information and inbound communication not only comprise signal message but also comprise data message.
Antenna circuit in each RTRX is transformed into the RF signal with outbound data from number format and sends to mobile radio station, and will become digital inbound data to handle for Cellular Networks from the RF signal transformation of mobile radio station.Though if desired, additional disposal ability can be built upon among the RTRX, and it is minimum would rather keeping the circuit in the RTRX usually, safeguards and upgrading so that simplify.In addition, because RTRX can be implemented to and (for example, provide the position of best transmission quality, as top of building or other structures) on the position that can arrive securely or be exposed under the weather key element, the least possible RTRX design helps robustness, reduces maintenance cost.
Fig. 6 illustrates the CBTS108a that comprises Abis interface 450 according to one embodiment of the invention.In CBTS 108a, antenna circuit is implemented among the RTRX subsystem 110a-110e.Though each RTRX illustrates with single antenna, the transmission of their available separation and one or more reception antenna are realized.Each RTRX preferably includes antenna circuit, for example, and radio interface circuit, and in up direction, the RF signal processing that receives is become will send to the circuit of (following discussion) binary data bit of CTRX.In addition, annual RTRX preferably includes and will be processed into the circuit of the RF signal that will send to mobile radio station from Cellular Networks (through CTRX) the descending binary data bit that receives.
A plurality of CTRX 452a-452b are embodied among the CBTS 108a.Each CTRX is linked a unique cover RTRX in any given time.In the embodiment illustrated, RTRX110a-110b is linked CTRX452a, and RTRX 110c-110d is linked CTRX452b.Connection between RTRX and its CTRX can comprise by any suitable transmission medium, as, twisted-pair cable, coaxial cable, or optical fiber carries out.In one embodiment, transmission medium is represented twisted-pair cable, utilizes a kind of digital baseband physical layer protocol (T1, E1, E2, E3, DS1, DS3, Deng), between CTRX and RTRX, transmit communication service data by the ATM(Asynchronous Transfer Mode) link, radio control and state.Another kind of optional or other scheme is to adopt Internet Protocol (IP) communication technology.Arrange though every group of RTRX shown in Figure 6 is daisy chain type, independent RTRX can link their relevant CTRX abreast.
Usually, the RTRX of any number can link a CTRX, can have a suitable identifier from the data of each RTRX, makes CTRX can discern the RTRX that sends data.In fact, the number of RTRX can be limited to rational number, be suitable for the disposal ability of CTRX or avoid RTRX and CTRX between transmission channel too much, if the physical layer of framing is E1 (30DSOs) on transmission channel 460a, the individual RTRX work of about 5 or 6 (if the capacity permission can be more) just, for E2 physical layer framing, about 22 (or more, if capacity allows) individual RTRX can by daisy chain type link a CTRX.For E3 physical layer framing, owing to bit rate bigger on transmission channel, greater number (for example, 88 or even more) RTRX can be connected by daisy chain type.
Because RTRX separates (for example, connecting through cable) at a distance with CBTS, CBTS does not need to consider the radix of sub-district.Utilize the present invention, each CTRX stipulates that effectively one is assembled the sub-district, is made up of the radio plot of relevant RTRX now.Can be dispersed in the sub-district Anywhere away from the RTRX of CTRX itself, it is to being interspersed between the RTRX relevant with other CTRX.Be to be appreciated that the multiplicity of RTRX group, and their easy location, in the moulding of sub-district, provide flexibility for the ISP in the mode that can not obtain simply in the prior art.
Independent radio plot certainly further utilizes traditional antenna technology moulding, for example, utilizes directional antenna or increases transmitting power.If transmitting power is increased, the treatment circuit to CBTS additional heat that is produced and power do not resemble in the situation of prior art BTS circuit causes danger, and the TRX of prior art is wireless and the BTS circuit is put together.On the other hand, typical situation is that a given zone that was covered in the past by high power TRX can be covered by each multiple RTRX that launches on lower power level equally.In this way, given zone can by one simple, the RTRX array of firm lower-wattage covers, thereby reduces the cost of implementing BTS widely, and make potential sub-district to the interference of sub-district for minimum, and/or improve channeling.In a given zone, provide equivalence or better cover in to adopt the ability of lower-wattage antenna be a great advantage of the present invention.
In Fig. 6, every group of RTRX is shown directly linked the CTRX relevant with it through suitable transmission medium.Fig. 7 describes another kind of optionally CTRX and RTRX embodiment, and route resource not only provided at RTRX but also in CBTX therein, so that will be for example, distribute to CBTS Digital Signal Processing (DSP) resource dynamic the RTRX of the sub-district of gathering.In this embodiment, RTRX110a-110e by daisy chain type link routing circuit 464.On the one hand, a kind of ATM(Asynchronous Transfer Mode) routing circuit of routing circuit 464 representatives.Another kind of optional or other scheme is to adopt Internet Protocol (IP) communication technology.A kind of database of controlling routing circuit 464, table, or intelligent algorithm determines which which RTRX is assigned among the CTRX452a-452c.In this case, each RTRX is relevant with a unique ATM or IP address, and be provided suitable ATM or IP framer circuit so that the RF packing data of demodulation is delivered to routing circuit 464, perhaps will unpack by ATM or IP packet that routing circuit 464 sends.Communication service data, radio control, and status data can be packaged into ATM or IP sub-district for transmitting between RTRX and the CTRX relevant with it, each sub-district is about two pulse trains at most.If use frame relay protocol can adopt analogue technique.
Fig. 8 represents the logic block-diagram according to a kind of embodiment R TRX 110a of the present invention.RTRX 110a comprises a radio parallel circuit 502, and its basic function is to send and receive RF information aloft.Two antennas are illustrated links radio parallel circuit 502; A transmitting antenna 504 and a reception antenna 506.Though, no matter receive transmitting antenna and can be integrated into a single antenna at two antennas this illustrate.
Radio interface parallel circuit 508 receives the packing data from physical layer framing/transmission farming interface parallel circuit 510, and downlink data is formatted into is pulse train, is sent to radio parallel circuit 502 in company with frequency and power information for pulse train.In one embodiment, frequency information itself regains from global positioning system (GPS) terminal, and utilizes timing phase-locked loop (PLL) parallel circuit 512 to be synchronized to suitable specification requirement (for example, GSM specification requirement).At receiver side, radio interface parallel circuit 508 is obtained demodulated data from reception antenna 506, and its packing is sent to CTRX through daisy chain transmission medium 518 (can implement, for example, E1 agreement).In one embodiment, utilize field programmable gate array (FPGA) to realize radio interface parallel circuit 508.
Digital Signal Processing (DSP) parallel circuit 514 is carried out to the modulation of the binary signal that receives from Cellular Networks so that through transmitting antenna 504 transmissions, to the RF signal demodulation that receives through reception antenna 506, and signal equalization.In one embodiment, implement DSP parallel circuit 514 by a kind of nextport universal digital signal processor NextPort (DSP).
A kind of read-only memory parallel circuit 520 store configuration data are used for configuration RTRX 402 when starting.Microcontroller 522 provides the internal affairs processing capacity, as status checkout, and diagnosis, and power management.In one embodiment, if find that RTRX has fault, microcontroller 522 may be utilized, just as, link together by input and output RTRX, take daisy chain loop RTRX 110a in addition.Microcontroller 522 also monitors the communication between RTRX and its CTRX homologue.In one embodiment, the communication between all RTRX and the CTRX realizes through physical layer framing/transmission farming interface parallel circuit 510.Physical layer framing/transmission farming interface parallel circuit 510 is finished following task: format and driving data receive and will go to format from the data that CBTS receives, and check the health status that control and monitoring connect to CBTS.
With reference to the exemplary embodiment of figure 9 and 10A-C, the work that can understand better between RTRX and the CTRX is divided.Fig. 9 is sending and reception period the block diagram of data flow in the GSM of prior art BTS module with explaining.The data that send to mobile radio station are received through Abis interface 602 by BSC.Voice go framing square frame 604 to extract numerical data from the Abis frame, and it is sent to chnnel coding square frame 606, its objective is the numerical data packing that will be extracted, are used for transmitting on the RF media at last.Data are inserted in the multi-pulse string in inserting square frame 608 then, make the risk of losing successive bit during sending for minimum.Then pulse train in burst format square frame 610 formatted and for safety can be chosen in encrypt in the square frame 612 encrypted.After this, numerical data modulated (for example, utilizing Gaussian Minimum Shift Keying) is in order to send to mobile radio station as the RF signal through Tx radio square frame 616.
At receiver side, be received at Rx radio square frame 650 from the RF signal of mobile radio station, and in demodulation/balanced square frame 652, be demodulated to numerical data and, if desired, in deciphering square frame 654, implement deciphering by balanced.Burst format square frame 656 extracts user data and utilizes suitable rhythm to constitute 148 pulse train it from speech frame.After this, removing to insert square frame 658 will re-assembly from pulse train group's data.Then, utilize channel-decoding square frame 660 with the numerical data dismounting, so that extract user data.The numerical data that framing of speech square frame 662 will have been dismantled forms the Abis frame, so that be sent to BSC.The function square frame of Fig. 9 is well-known for the technical staff in GSM field.Just as mentioned, for realizing the required circuit of function square frame of Fig. 9, in typical case, realize in a box in the prior art that just, these circuit are put together in prior art BTS.
In contrast, according to one embodiment of the invention, Figure 10 A is illustrated in and sends and reception period, the data flow in the CBTS of the present invention.In Figure 10 A, Abis interface square frame 602, and the square frame on downlink path 604,606,608,610 and 612 and up path in square frame 654,656,658,660 and 662 finish basically with Fig. 9 in corresponding square frame identical functions.For the ease of the telecommunication between CTRX and RTRX, the physical layer framing and the transmission farming function square frame that add in the interpolation.At transmitter side, these illustrate as transmission farming interface square frame 702 and 708, and transmission farming interface square frame 702 is put together with CBTS, and its homologue transmission farming interface square frame is realized in RTRX.As mentioning in the past, transmission farming can adopt well-known ATM agreement, IP agreement or frame relay protocol.
Also at transmitter side, become frame interface square frame 704 and 706 to realize for the physical layer framing of communicating by letter between RTRX and the CTRX by physical layer, physical layer becomes frame interface square frame 704 and CBTS to put together, and its homologue physical layer becomes frame interface square frame 706 to realize in RTRX.In one embodiment, because the numerical data of encrypting is exported from encrypting square frame 612, it is packaged into ATM or IP frame (square frame 702), and is sent (square frame 704) by framing through the E1 agreement.These data are sent to RTRX through transmission link 710.When receiving data, RTRX is from E1 frame extracted data (square frame 706), and data are unpacked (square frame 708).The data of having unpacked then modulated (square frame 614) also send to mobile radio station through sending radio square frame 616.
Notice that line 720 is illustrated in the boundary between function square frame of realizing among the RTRX and the function square frame of realizing in CBTS/CTRX.In fact, will be implemented single CBTS/CTRX box (even in certain cabinet on the identical backboard) at the function square frame of Figure 10 A center line more than 720.And the function square frame of line below 720 will be implemented in RTRX, is positioned in typical case to leave certain distance of CBTS/CTRX.This structure is different from the BTS of prior art among Fig. 9, and the main square frame of all shown in it is put together with BTS.
At the receiver side of Figure 10 A, receive by Rx radio square frame 650 and in demodulation/balanced square frame 652, be demodulated to numerical data from the RF signal of mobile radio station.Demodulated data, and the RF high-quality data that obtained in balancing procedure are sent to CTRX through transmission farming interface square frame 760 and 766.Provide physical layer to become frame interface square frame 762 and 764 once more, be convenient to demodulating data framing.So that transmit by physical layer protocol.If in a kind of antenna diversity is used, provide multiple RTRX, for example, can adopt selectable RF quality to select square frame 768, in RTRX, select to provide best transmission quality one.Notice that this selection can be carried out before any transmission user data, for example, when being exhaled mobile radio station to answer the liaison signal of automatic network.After this, from the data of selected RTRX decrypted (if desired), format goes to insert, channel-decoding and through square frame 654,656,658,660 and 662 framing before being sent to BSC through Abis interface square frame 602, are undertaken by the contact mode that Fig. 9 discussed.
Though the division between RTRX and the CTRX occurs between encryption in the sending direction and the modulator blocks and between the deciphering in receive direction and the demodulation/balanced square frame, this is not a kind of restriction of the present invention.In fact, consider can to occur in cutting apart between remote and CTRX send and RX path in any one.Figure 10 B illustrates a kind of exemplary application, wherein between other square frames that occur in BTS cutting apart between remote and the CTRX.In Figure 10 B, cut apart the voice that occur in the transmit path and go between framing and the chnnel coding square frame and between framing of speech in the RX path and the channel-decoding square frame.Certainly, if desired, cut apart between the square frame that can occur in any other.
Also notice, need be between RTRX and CTRX being segmented in send and RX path in be symmetrical.Figure 10 C illustrates a kind of exemplary embodiment, and it is asymmetric wherein cutting apart, and transmit path circuitry is more than the RX path circuit in CTRX.Again, RTRX and CTRX can divided transmission and RX path in accurate position be that embodiment is distinctive.B. network function
Structure of the present invention and parts can be finished the present invention and are served many functions of improving cellular call processing and route.Cellular Networks designer can design such RTRX, makes them be placed on and obtains on the position maximum and the most flexible covering.Some RTRX will be placed on and think to have on the position of high number mobile radio station, and will being placed on of other thinks to have on the position of low number mobile radio station.When network is activated, mobile radio station will move in the space, and the activity of network will change.Some novel function described below is designed to improve the problem relevant with the network activity that is changing and the activity of desired increase network is provided.
1) frequency agility by RTRX
Usually, if necessary, RTRX will be placed mutually adjacent to each other, makes mobile radio station can insert more than 1 RTRX.This respect of the present invention comprises each RTRX broadcast beacon in portion of time, as 1/4 time, rather than All Time.When the mobile radio station off-hook, the RTRX that is exporting beacon frequency will discern the mobile radio station of off-hook and begin and the mobile radio station session.RTRX will whether this mobile radio station be certified from the MSC inquiry, and MSC will order RTRX to distribute specific frequency of this mobile radio station (may be a frequency agility sequence) then.Mobile radio station will begin communication by the order of RTRX then.
When another mobile radio station off-hook, beacon frequency may be that mobile radio station will be assigned to that RTRX from different RTRX emissions, and this will call out the complexity that starts and download to multiple RTRX, so that call load is distributed between RTRX.As a result, network provides improved frequency diversity, improved covering and improved service quality.
2) diversity reception/transmission
Once more, because RTRX is often placed mutually adjacent to each other, make mobile radio station can insert more than 1 RTRX, one aspect of the present invention is that network is carried out diversity feature.When a mobile radio station was sending its outbound information, several RTRX can receive this information.When this happens, one among the RTRX will receive signal preferably than other RTRX, best signal priority is received by the RTRX of the best, inbound communication reorganization in CBTS or BSC (perhaps or even MSC) is so that catch all inbound communications and this information editing is become inbound communication completely.
This diversity feature is based on such supposition, and promptly network has some too much capacity sometimes.When having too much capacity, diversity feature can guarantee optimum reception to signal be used to edit inbound communication.
At this respect of the present invention, the outbound information of mobile radio station is implemented by one among the RTRX that distributes to mobile radio station.Decision is given this mobile radio station handover on the position of another RTRX if mobile radio station moves to MSC, and handover is implemented so, and newly assigned RTRX is sent to this mobile radio station with outbound information.
In antenna diversity is used, each CTRX represents the RF channel of a separation during use in essence, data from given mobile radio station in the sub-district can be obtained more than 1 RTRX, therefore, CTRX preferably includes the RF quality and selects circuit 454a, selected RTRX is used to select to have the RTRX of the best that first water receives, so can be used to during calling out and mobile station communicate.In antenna diversity was used, because each CTRX represents a RF channel with the RTRX group relevant with it in any given time, the mobile radio station of communicating by letter on this channel can be obtained more than 1 RTRX.With reference to figure 6, for example, can be arrived by the antenna detection that RTRX organizes in the 110c-110e from the RF signal of mobile radio station 111a.CTRX 452b comprises RF quality selection circuit 454b, is used for selecting to provide among RTRX group 110c-110e the best RTRX of best transmission quality.Provide best transmission quality if realize RTRX 110d, CTRX452b can adopt the antenna in RTRX 110d to be used for communicating by letter with mobile radio station 111a subsequently.In one embodiment, can be by receiving the equalizer quality and making comparisons from the received signal indicating device intensity (RSSI) of each RTRX and from the value that receives, choose optimum value and finish selection.In tdma system (GSM), this selection can be carried out each TDMA pulse train.
With reference to figure 7, utilize routing circuit 464 to help that easily dynamic DSP is carried out in the gathering sub-district relevant with CTRX452a-452c and distribute, so that handle in the variation of capacity aspect needing.Dynamic-configuration can realize that they are that routing circuit 464 is in order to transmit data between CTRX and RTRX by simple change routing table or database.Method by way of example, at time T o, RTRX110a can be sent to CTRX452a, and RTRX110b can be sent to CTRX452b and RTRX110c-110e can be sent to CTRX452c.If near the capacity RTRX110d-110e increases in time T 1, or it is interim or permanent, can adopt dynamic DSP to distribute, data are sent to its CTRX452c from RTRX110e, be sent to its CTRX452b from RTRX110d, remaining RTRX110a-110c is redistributed to CTRX452a.Because after reconfiguring, must not share CTRX near zone the RTRX110d and near the zone the RTRX110e, in these zones, can handle more capacity.Such just as this field technicians can recognize, as RTRX or CTRX is coupled with or when CBTS removed, dynamic DSP distributed the task of simplifying the capacity of redistributing widely.
Generally, in a given CBTS for the number of enforceable CTRX without limits.In fact, the number of CTRX is corresponding with the processing capacity of CBTS in proportion (dynamically DSP distributes embodiment if desired, and is also corresponding with routing capacity).Give BTS because each additional CTRX increases an additional RF channel, wish to give the enough disposal abilities of CPU460 of Fig. 6 and 7, to guarantee that all callings are suitably handled.Give an example, in a kind of application of non-antenna diversity, each remote radio can provide a GSM frequency channels (8 communication traffic channel).Depend on the design of CTRX, CTRX can handle the RTRX (in an example about 8 to 16) of any number.In certain embodiments, can adopt parallel processing technique to make CBTS can handle a large amount of CTRX.It is in the technical capability scope of the technical staff in the field that present disclosure provides that such CPU operates in proportion.
3) soft handover
Aspect diversity reception/transmission of the present invention, can carry out soft handover.When being lower than the threshold value of predesignating, carries out the incoming level on the RTRX that is distributed this operation.When such reduction took place, mobile radio station can be assigned to the 2nd RTRX that is receiving strong signal.In this case, the 2nd RTRX may be such RTRX, and it is sent to MSC with inbound communication from mobile radio station in the several nearest image duration of diversity feature.
In order to realize soft handover, CBTS, BSC and MSC are configured to determine when that the inbound communication power level for RTRX is reduced to below the threshold value of predesignating.Threshold value can be measured with watt, but the relative intensity that also available and contiguous RTRX compares is measured.
4) radio hookup
This respect of the present invention comprises from a plurality of RTRX and sends outbound information simultaneously.This can be thought of as a kind of broadcasting, and wherein Guang Bo covering comprises that RTRX is identified the sub-district that sends outbound information.It is favourable that the announcement that this respect of the present invention relates to all mobile radio stations for issue is sent to a plurality of mobile radio stations simultaneously.For example, if this network is positioned at an airport, radio hookup can comprise other information of flight signal or relevant many mobile radio stations.This is called as Cell Broadcast CB, has been the characteristics of a kind of ETSI.
In addition, can dynamically distribute the radio hookup function to give RTRX by on the basis of pulse train one by one.Intelligently realize radio hookup.For example, if each pulse train frame have the ability to be supported 8 mobile radio stations, and to have only 8 mobile radio stations be used, and then each among near the RTRX 8 mobile radio stations will be broadcasted exit signal.Yet, if additional mobile radio station off-hook, one of radio hookup pulse train of among near 9 mobile radio stations the RTRX each is dynamically reconfigured, make one of RTRX will with the 8th mobile station communicate, another RTRX will with the 9th mobile station communicate, continue simultaneously the radio hookup of the 1st to the 7th mobile radio station.
The problem that problem is a zero-signal that in the radio hookup technology, may cause.Zero-signal is such position, produces destructive interference mutually at this exit signal from RTRX and causes zero energy occurring on this position.In order to relax this problem, zero-signal can make the neither one mobile radio station bear lasting zero-signal by periodically in spatial movement.The technology that is used for mobile zero-signal comprises power ramp up, and wherein the radiant power of RTRX is by periodic variation, frequency agility, and wherein communication frequency is by periodic variation and clock shake, and wherein timing clock is by periodic variation.
5) mix and mate the ground spectrum standard
In the diversity of identification communication standard, the present invention can adopt the RTRX that can communicate by letter under various standards.Between CBTS and RTRX the interface of defined can be still as described in the present technique explanation, but the interface of defined can change between RTRX and mobile radio station.For example, one type RTRX can be constituted as and adopt the mobile station communicate of 1800MHZ GSM standard, another kind of type can be constituted as and adopt the mobile station communicate of 1900MHZ GSM standard, another kind of type can be constituted as and adopt the mobile station communicate of 900MHZ GSM standard, and other type can be constituted as and adopt other standards such as CDMA, AMPS, the mobile station communicate of digital AMPS etc.
6) transfer between the BTS
To understand characteristics of the present invention be that the main person of exhaling will many times call out mutually in network from considering to install easily network.Consider that a site technology person taking to influence before the action of other services, may want to communicate by letter with his manager or other technologies person, this is significant.In this case, this technician will be at on-net call.Several other similar situations are to understand easily for those skilled in the art.In this respect of the present invention, calling exchanges so that finish calling in private network.In this case, calling does not need to be returned on the way to drag up to MSC.This minimizing is called out returns to drag and causes lower administration overhead and less signal contact.In order to realize exchange, carry out a kind of signals step of falseness, pretend this callings and time dragged.This is called as false Abis, is described in U.S.Pat.No.5, in 734,979.
7) reliability and quality are restored and fault-tolerance.
Utilization is than relatively large RTRX and CBTS, and network shows very good quality, restores and fault-tolerance.For example, because many RTRX can closely be placed mutually, the parts of the replaceable fault of parts of job network.Then, can be under the situation of not destroying service the parts of repair a breakdown.
8) based on the distribution of adding up
Another aspect of the present invention relates to a kind of technology of balancing network traffic load.In this respect, if RTRX bears the heavy burden of message volume, some communication is transferred to other contiguous RTRX that can accept to communicate by letter.With reference to figure 1, suppose that many mobile radio stations are collected near in the zone of RTRX110c.RTRX110c will and will attempt and each mobile station communicate of off-hook in this zone with mobile station communicate.Yet this will make RTRX110c bear heavy load, and will make the communication service between RTRX110c and the CBTS108a very heavy.Utilize a kind of technology, some mobile radio station of communicating by letter with RTRX110c is transferred to RTRX110b communicates by letter.This just provides service for the load that is equilibrated on the RTRX110c, though the signal quality between mobile radio station and RTRX110b can not be good as RTRX110c.This result is the communications traffic load of this systematic comparison the best of balance.In this first technology, remain heavy to the message volume of CBTS108a, so second technology is described in order to alleviate load.In second technology, preferentially award the RTRX that links different CBTS.In this technology, mobile radio station will be transferred to RTRX110f.This provides double advantage, downloads some communication service from RTRX110c and CBTS108a, and this load is moved to RTRX110f and CBTS108c.
In one aspect of the invention, based on these technology, the present invention can balanced communication load on the basis of pulse train one by one.Can by on the basis of pulse train one by one dynamically distribution function give RTRX, intelligently realize balance.For example, when mobile radio station was concentrated in the ad-hoc location that service is provided by network, other RTRX came the balanced communication load to network by mobile station communicate being transferred to optionally.This distribution can be at pulse train one by one or is realized on the basis of frame one by one.
9) covering and quality improvement, BSC-BSC communication
With characteristics like the communication class between the BTS is that BSC-BSC communicates by letter.Consider that many callings are dealt in the network, these characteristics are favourable.In this aspect of the invention, calling is exchanged in private network so that finish calling, and calling out does not need from the beginning to be returned on earth to drag up to MSC.Thisly cause lower administration overhead and less signal to calling out back the minimizing of dragging.In order to realize exchange, a kind of signals step of falseness is implemented, and pretends this callings and time is dragged.This is called as false A, as U.S.Pat.No.5, described in 734,979.
10) OMC function.
The OMC112 monitoring network.In one aspect of the invention, OMC comprises a network topology memory 206, comprises the image and the geographic topological structure of recognition network component locations.OMC provides network state information by user interface 210.OMC collects the statistics that comprises traffic load and crowded state information.It is useful that this information makes the growth that is adapted to mobile radio station for network planning person regulating networks.Such as described above, it also is useful to the traffic load of calling out and be equilibrated between the RTRX that this information is distributed RTRX for activity network.
OMC can recognition network running parameter, so network will have different selections.For example, in a kind of common network, the TRX with maximal received power level is assigned to mobile radio station.The present invention can be modified running parameter, so as to give current not with the RTRX preoption of mobile station communicate, preferential chance is provided perhaps for the RTRX that compares with some other RTRX with less mobile station communicate.This modification will trend towards the traffic load in the balancing network.
OMC also comprises incident management, alarm and user management.Incident management comprises the function of recognition network incident, as the communication service overload of network, and the error condition indication of a kind of fault (for example parts of a breaking-up), or other similar incidents.Also can write down the disturbance regime that occurs between network components and the mobile radio station.This information for make the technician can or the regulating networks communication service to be adapted to the loaded condition of communicating by letter, perhaps discerning error condition or other incident is helpful for the usefulness of correct repairing.OMC also serves and carries out test and maintenance program, the health status of supervising network.C. another kind of optionally structure
1) combination
Structure depicted in figure 1 can utilize unit construction to be compressed, as U.S.Pat.No.5, described in 734,979.In this respect of the present invention, it is a kind of modular that Figure 11 describes to utilize TDM bus and VME bus how to realize, can pro rata structure.Frame 800 provides support for VME bus 254a and TDM bus 254b along backboard.Parts as CPU252, as technically known, are positioned in the frame, link on the backboard by connector.Parts also can be formed in single, two, or on many printed circuit boards.The last network components of these parts regulations.CPU252, DSP802 and CTRX804 not only link VME bus 254a but also link TDM bus 254b.Clock module 806 is linked TDM bus 254b and is produced Reference clock, makes each subsystem can be with method of synchronization work.Trunk module 256 is not only linked the VME bus but also is linked the configuration that TDM bus: Figure 11 describes an a kind of TRX BTS, is also depicted among Figure 12.
Figure 12 and 13 describes the network components that is made of the parts of linking in the base plate 800.Figure 12 describes to have the CBTS of two CTRX, and RF distributes card, CPU and E1 card.Base plate can be used as an independent cell operation, perhaps can be installed on the frame of equipment so that be deployed in the scene.And any card can be placed in any groove.By removing all CTRX, it is possible only utilizing trunk module and CPU card formation BSC or MSC configuration.
Because this structure is fully can be pro rata, Figure 13 describes a kind of 6 TRX that have, the base station of 2 CPU and 3 trunk modules.The configuration and the function of any base station can be provided by the processing unit of selecting to be used to dispose.Utilize the present invention can realize various possible functions, as BTS, BSC, the BTS/BSC of combination, MSC, the BTS/BSC/MSC of the BSC/MSC of combination and combination.When cpu function was merged in CTRX processor and the trunk module processor, the configuration with single CTRX and single trunk module was possible.
For the function that realizes stretching, adopt trunk module 256 to adapt to different information rates.Get back to Fig. 5 A-B, framer 410,412 is linked time/space switching 402 by 2Mbps framer mouth TxA and TxB.2Mbps is a kind of E1 interface rate, but can be modified to any interface rate.Framer 410,412 is configured to and other network componentses, as BTS, and BSC, MSC, PBX, PSTN waits communication.Because the base station can be configured to carry out BTS, BSC, or the function of MSC, the type of interface can be changed to adapt to specific needed interface function.For example, the E1 that the framer 410,412 shown in Fig. 7 can 2Mbps, 1, the T1 of 544Mbps, the DSO of 64kbps, or other digital interface engages.
Figure 15 describes a kind of network configuration, and wherein BSC is combined on the identical base plate with the CBTS function.The base plate that is configured to carry out this network components can have a plurality of CTRX, a trunk module, and a CPU, clock card and RF distribute card.The routing function that is used for calling out by BSC or CBTS transmission described above is transmitted by the BSC/CBTS combination now.In order to realize some switching technology, Abis interface is implemented as false Abis, as U.S.Pat.No.5, described in 734,979.
Figure 16 describes a kind of network configuration, and wherein MSC is combined on the identical base plate with the BSC function.The base plate that is configured to carry out this network components has a trunk module, a CPU and a clock card.Described above, be used for transmitting the routing function of calling out and transmit by the MSC/BSC combination now by MSC or BSC.In order to realize some switching technology, the A interface is implemented as the A of a falseness, as U.S.Pat.No.5, described in 734,979.
Figure 17 describes a kind of network configuration, MSC wherein, and BSC is combined in the identical base plate with the CBTS function.The base plate that is configured to carry out this network components can have multiple CTRX, a trunk module, and a CPU, a clock card and a RF distribute card.Described above is used for by CBTS, and BSC or MSC transmit the routing function of calling out and transmitted by the MSC/BSC/CBTS combination now.In order to realize some switching technology, the A interface is implemented as a kind of A of falseness, and Abis interface is implemented as a kind of Abis of falseness, as U.S.Pat.No.5, described in 734,979.
Important advantage that can pro rata structure is when the trunk module card is coupled with, and the exchange capacity of base station increases.For example, have the base station of 3 trunk modules by configuration, as shown in Figure 13, base station ability is added to 6 E1 delivery outlets.This configuration both provided the communication capacity bigger to MSC, was provided at the inner bigger information exchange ability in base station itself again, as between the CTRX card.
2) another kind of optionally communication structure
Figure 18 describes a kind of loop configuration 900, and wherein the BSC/CBTS parts 130a of BSC parts 106a-106b and combination comprises a kind of structure, by bus 904 exchange message between separately CBTS110a-110r and MSC102.Bus 904 can be E1, for example, utilizes the ATM agreement, IP agreement or frame relay protocol transmission information to and from network components.A kind of subnet is configured with CBTS108a and 108b, by these parts being connected to bus 908 and BSC106a realizes.This configuration is good, because each network components has being used to transmit between mobile radio station in network and the PSTN104 inlet of other network componentses of information.D. conclusion
The invention provides many advantages that are better than known technology.An advantage of the invention is that transmitter-receiver obtains the large-area covering of communicating by letter with disposing flexibly to make up with low cost cheaply.This honeycomb that just allows the cellular system engineer to be designed for real any physical space covers.The additional advantage of various aspects of the present invention comprises modularization, can be in proportion, and distributed treatment, improved performance reduces network congestion, and fault-tolerance and more effective has cost-efficient base station.
Particularly, because multiple RTRX can be linked single CTRX, each CBTS can have a plurality of CTRX, and structure of the present invention provides big flexibility aspect allocating cell.The shaping of sub-district no longer is subject to the range of transmission of revising antenna pattern and centering on BTS.Utilize CBTS structure of the present invention, the RTRX that cable can disperse from the geography that a CTRX leads to any number, the sub-district of the outer gathering of telogenesis of the radio plot of Fen Saning geographically.And then, utilizing the multiple CTRX among each CBTS, the ISP has the useful instrument that is used to dispose Cellular Networks.
These cheap low-power RTRX may be utilized to substitute the high power TRX of the prior art that covers same area now.Except the cost that reduces radio circuit, the present invention also utilizes channeling, because each radio plot (relevant with each RTRX) can be littler.Also as discussed above, dynamically the ability that one or more RTRX and given CTRX are got in touch offers the ISP reconfiguring big flexibility aspect the sub-district, adapts to the variation of capacity aspect to utilize existing RTRX/CTRX group or additional RTRX/CTRX.
Disclose exemplary embodiment and best pattern, can make amendment and modification, and still remained in the scope of the present invention as following claim defined for disclosed embodiment.