CN201035821Y - Mobile communication experiment system - Google Patents
Mobile communication experiment system Download PDFInfo
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- CN201035821Y CN201035821Y CNU2007200368856U CN200720036885U CN201035821Y CN 201035821 Y CN201035821 Y CN 201035821Y CN U2007200368856 U CNU2007200368856 U CN U2007200368856U CN 200720036885 U CN200720036885 U CN 200720036885U CN 201035821 Y CN201035821 Y CN 201035821Y
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Abstract
The utility model discloses a mobile communication experiment system, and relates to a communication experiment system which tightly combines a mobile communication course, and verifies technology in the mobile communication. The mobile communication experiment system comprises an experiment box, a student platform, a teacher monitor console, and a minitype telephone exchanger; the experiment box comprises a mobile terminal part, a base station part, a central controller, a special experiment module, and a GSM wireless MODEM module; the mobile terminal part comprises an audio input/output interface, a direct-current level controller, a PCM/ADPCM codec, an LPC voice companding codec, a channel coder/decoder, a framer, a modem (DSP), a channel shaper, and a wireless receiving and sending radio frequency module; the base station part comprises an exchanger interface, a hand-free audio power amplifier, a PCM/ADPCM codec, an LPC voice companding codec, a channel coder/decoder, a framer, a modem (DSP), a channel shaper, and a wireless receiving and sending radio frequency module; the central controller comprises a monolithic processor (CPU), a RS232C communication port, and interfaces of 16C550 GSM MODEM communication, etc.
Description
Technical field
What the utility model mobile communication experimental system related to is a kind of mobile communication course of combining closely, the communication experiment system that relates to technology in the checking mobile communication, experiment is introduced typical technology in the current mobile communication by terminal technology and network technology, and is different from the former communication technology.The mobile communication terminal technology experiment comprises the experiment of following several parts: information source encoding and decoding experimental section, channel coding/decoding part, modem section.These experiments are all finished under the cooperation of student's platform by the correlation module on the experimental box.The network technology experiment comprises system experimentation part, 900MHz GSM mobile handset system experimentation part.This system mainly supply college student (containing junior college, undergraduate course, postgraduate) or teacher experiment or research with, also can be used for the training organization that is correlated with.
Background technology
Present mobile communication experiments experiment system has the following disadvantages:
1. test singlely, can only check waveform simply, systematicness is not fine;
2. so-called base station is not made an anolog base station veritably and is come out in the experimental system, and the experiment of 900MHZ mobile phone has just simply been done individual mobile module, can only do conversation simply and testing, and the student is not had much good;
3. can not utilize AT to instruct to understand the Signal Processing process of terminal this part in the mobile communication all sidedly;
4. can only see corresponding single waveform after the modulation in the modulation experiment, and can't test the waveform of each link correspondence in the modular system;
5. basic all appts only satisfies simple authentication function, and the student does not participate at all, can't improve students'ability for practice veritably
These weak points have seriously hindered the raising of students ' practical ability, can not improve the quality of teaching efficiently.
Summary of the invention
The utility model provides a kind of mobile communication experimental system at above-mentioned weak point, develops on the basis of teaching material of combining closely, and its framed structure also is to work out according to the structure of gsm mobile communication system.Gsm mobile communication system comprises parts such as mobile terminal MS, base station sub-system BS (comprising base transceiver station BTS and base station control center BSC), the MSC/VLR of switching centre, user attaching location register HLR/AUC database.As the simulation to actual mobile communication system, this mobile communication experimental system also will realize the function with top accordingly.
The mobile communication experimental system is to take following scheme to realize: the mobile communication experimental system comprises experimental box, student's platform, teacher's control and monitor console, small branch exchange.
Experimental box comprises portable terminal part, base station portion, central controller, special experiment module and gsm wireless MODEM module.Portable terminal comprises that partly audio frequency input/output interface (receiver interface and microphone interface), DC level controller, PCM/ADPCM codec, LPC voice companding codec, channel coder/decoder, framing, modulator/demodulator DSP, channel form device, wireless receiving and dispatching radio-frequency module.Base station portion comprises that exchange interface, hands-free audio amplifirer, PCM/ADPCM codec, LPC voice companding codec, channel coder/decoder, framing, modulating/demodulating DSP, channel form device, wireless receiving and dispatching radio-frequency module.Central controller comprises that single-chip microcomputer (CPU) AT89C55WD MCU control core, RS232C communication port, 16C550 GSM MODEM communication interface, spi bus interface, ADPCM communication interface, DSP exchanges data and program load communication interface, LC4384 ISP data-interface (CPLD), LCD display interface, keyboard interface, DSP HPI interface and IO IO interface.Special experiment module comprises the IO interface of LC4384 ISP programmable logic device (PLD), data processing memory (62256), ISP DLL (dynamic link library), MCU communication interface, general use.Gsm wireless MODEM module comprises GSM MODEM module, SIM card, resets, powers on and Audio Processing/change-over circuit.
Experimental box: the mobile communication experimental box has mainly been simulated the treatment technology of communication terminal, the treatment technology of wireless base station.And by wireless channel connection, the wireless access of analog telephone signal.Mobile experimental box is provided with some, mobile experimental box is equipped with PC system and software, simulated mobile switching network by LAN (Local Area Network) and small branch exchange, realize the experiment that experiment, mobile management, transfer table call treatment were landed and shut down to mobile platform started, comparatively Xing Xiang explanation the principal character of mobile communication.Mobile experimental box also is furnished with standard GSM/GPRS communication module, carries out speech and data communication by any user in software control realization and the real network.Can also finish the information source encoding and decoding on the experimental box, channel coding/decoding interweaves and experiment such as scrambler, modulation.
Student's platform: student's platform is a microcomputer (PC), and it links to each other with experimental box by serial ports, links to each other with teacher's platform with other student's platforms by LAN (Local Area Network).Student's platform is that the student controls the platform that experimental box carries out corresponding experiment.Each experiment, the student enters the corresponding experiment interface of student's platform, and student's platform program can issue the control corresponding instruction to experimental box, the configuration relevant parameters, thus make experimental box carry out the preparation of corresponding experiment.The part result of experiment also will be sent on student's platform by experimental box by serial ports, and student's platform can clearerly be seen the part result of experiment by the interface.The concrete function of student's platform in each experiment is referring to the teachings of each experiment.In system experimentation, the effect of student's platform is very many, comprises following several respects: the effect of (1) mobile phone interface: buttons such as the start that exists on the general mobile phone, dialing, on-hook, shutdown will be arranged on student's platform.The student presses corresponding button, and student's platform is translated into corresponding message with these actions and sent to experimental box, and the MS of experimental box and BS begin corresponding signalling interactive process.(2) effect of signalling analysis and demonstration: in order to allow the student understand the signaling procedure between each functional unit in the GSM network.Signaling between MS, BS and the MSC all will be shown on student's platform.Therefore MS and BS receive that whenever a message all will be to the report of student's platform on the experimental box, and student's platform shows on the interface.At this moment, student's platform has just served as the effect of Signaling Analyzer in the reality.(3) effect of part MSC/VLR: student's platform also will be finished the function of part MSC/VLR in calling out control.Set up in the process with the mobile communication of other experimental group, the signaling of calling out control need be sent to other student's platform by student's platform by internal network.(4) maintenance of each functional unit parameter and demonstration: in order to allow the student understand the influence of specific signaling procedure to each functional unit parameter, student's platform will be safeguarded four parameter lists: MS parameter list, BS parameter list, MSC/VLR parameter list, HLR parameter list.Before system experimentation began, these parameters of student's platform were issued by teacher's platform, these four tables of list initialization that student's platform utilizes teacher's platform to receive.And the partial parameters of MS parameter list, BS parameter list to be handed down to experimental box by serial ports.After the experiment beginning, these four parameter lists of student's platform can change with the signaling process.After some specific signaling procedures, the student can observe the situation of change of each parameter list by the interface of student's platform.To the maintenance of MSC/VLR parameter list, the function of VLR database in the real system that has been equivalent to student's Platform Implementation.
Teacher's control and monitor console: teacher's control and monitor console links to each other with all student's platforms by LAN (Local Area Network).The effect of teacher's control and monitor console has: the work of control student platform.In the system experimentation part, be responsible for issuing of parameter lists such as HLR, MS.To safeguard a parameter list database on teacher's control and monitor console, after the experiment beginning, student's platform will be visited this database and be obtained the parameter list relevant with this student platform.To the maintenance of HLR parameter list, the function of HLR database in the real system that has been equivalent to teacher's Platform Implementation.Teacher's control and monitor console adopts microcomputer (PC).
Small switch: the effect of switching equipment is to finish two Speech Communications between the MS.In the experiment of transfer table calling procedure, caller and called between after Signalling exchange finishes, switching equipment is finished continuing of speech between two student's platforms.In actual mobile communication system, speech and signaling except between BS and the MS by the wireless channel transmission, remainder all transmits by wire message way.Carry out voice connection with Private Branch Exchange PBX and simulated in the actual mobile communication system voice signal in the transmission of wireline side: the called BS of caller BS-caller MSC-called MS C-.
By the introduction of above each module, we can know the corresponding relation of seeing this experimental system and real system: the function of corresponding MS of experimental box and BS; Finish the function of MSC/VLR on student's platform, in caller and called experiment, finish the process that customer call is set up on the one hand, safeguard VLR database on the other hand; Teacher's platform is safeguarded HLR database.The corresponding relation of interface is as follows: wireless radio interface is equivalent to the Um Interface in the GSM real system on the experimental box; Serial ports between experimental box and the student's platform is equivalent to the A interface in the real system; Interface function between VLR, HLR, the MSC is by student's Platform Implementation.
The utility model characteristics:
1. in the experiment that experimental box can be offered, contained each related in mobile communication system link: the detailed process of information source coding, chnnel coding, signaling structure and signaling, modulation, channel simulator, channel equalization, channel multiplexing mode etc.
2. information source encoding and decoding experiment: not only introduce classical voice coding PCM, 32K ADPCM, 16K ADPCM, and introduced the efficient voice compressed encoding and decoding technology that is widely used at present in VoIP and the digital speech transfer system, as based on Regular-Pulse Excitation long-term forecasting (RPE-LTP) scrambler (being adopted) of hybrid coding, based on the AMBE algorithm coding (proposing) of linear prediction sign indicating number excitation etc. by U.S. MIT by gsm system.
3. channel coding/decoding experiment: produce, encode, generate links such as random error, decoding and Bit Error Code Statistics by random information, allow the student understand the principle and the error correcting capability of channel coding/decoding; Simultaneously, opened the CPLD hardware resource, the student can be adopted under the instruments such as hardware description language VERILOG, HDL and ispEXPRESS, carried out, deepened the understanding of student, can be familiar with the application of CPLD in chnnel coding simultaneously chnnel coding from main programming.
4. modulation experiment: carrier synchronization, bit synchronization (sign synchronization) in each demodulation experiment have all adopted real real-time synchronization scenario; Simultaneously, in each link of modulation, be provided with a lot of observation point, the student not only can observe these observation point by oscillograph, also adopted the technological means of virtual instrument (virtual oscilloscope), the data acquisition of each observation point in computing machine, can be observed, operation such as comparison, convergent-divergent synchronously.
5. system experimentation emulation: complete regulation according to GSM 0407 in the 3GPP standard and GSM0408 standard, realized signaling processes such as start login, caller, called, mobile management, the student can detail knowledge in these flow processs three any incidents that protocol layer took place of aerial interface; And, be provided with the single step working method, can be as the film slow motion each process of detailed demonstration, also can send various signalings separately to portable terminal and base station.At present any other the like product of these unique advantages of system experimentation is all incomparable.
6. 900MHz gsm system experiment: not only can do caller, called, short message receiving-transmitting experiment, can also do the experiment of GPRS data transmission; Simultaneously, open transparent command format, the student can attempt other various AT orders, nearly kinds more than 100.
7. because experimental box has adopted the mentality of designing of software radio, experimental box can carry out channel simulator simulation and channel equalization, and from now on can also be according to the requirement of teaching and the progress of technology, carry out Software Secondary Development, only need to change software, just can realize system upgrade easily, greatly save user's investment, keep the advance of system simultaneously.
8. the mobile communication experimental system is under the overall background that current mobile communication is developed by leaps and bounds, and according to teaching demand, the suggestion that combines many experts of colleges and universities and teacher develops, and integrates advance, practicality, economy.
Description of drawings
The utility model is described in further detail below with reference to accompanying drawing.
Fig. 1 is a mobile communication experimental system structured flowchart.
Fig. 2 is the experimental box electronic schematic of mobile communication experimental system.
Embodiment
With reference to accompanying drawing 1,2, the mobile communication experimental system comprises experimental box, student's platform, teacher's control and monitor console, small switch.
Experimental box comprises portable terminal part, base station portion, central controller, special experiment module and gsm wireless MODEM module.Portable terminal comprises that partly audio frequency input/output interface (receiver interface and microphone interface), DC level controller, PCM/ADPCM codec, LPC voice companding codec, channel coder/decoder, framing, modulator/demodulator DSP, channel form device, wireless receiving and dispatching radio-frequency module.Base station portion comprises that exchange interface, hands-free audio amplifirer, PCM/ADPCM codec, LPC voice companding codec, channel coder/decoder, framing, modulator/demodulator DSP, channel form device, wireless receiving and dispatching radio-frequency module.Central controller comprises that single chip computer AT 89C55WD MCU control core, RS232C communication port, 16C550 GSM MODEM communication interface, spi bus interface, ADPCM communication interface, DSP exchanges data and program load communication interface, LC4384 ISP data-interface (CPLD), LCD display interface, keyboard interface, DSP HPI interface and IO IO interface.Special experiment module comprises the IO interface of LC4384 ISP programmable logic device (PLD), data processing memory (62256), ISP DLL (dynamic link library), MCU communication interface, general use.Gsm wireless MODEM module comprises GSM MODEM module, SIM card, resets, powers on and Audio Processing/change-over circuit.
Experimental box: mobile communication experiment cabinet has mainly been simulated the treatment technology of communication terminal, the treatment technology of wireless base station.And by wireless channel connection, the wireless access of analog telephone signal.Mobile experimental box is provided with some, mobile experimental box is equipped with PC system and software, simulated mobile switching network by LAN (Local Area Network) and small branch exchange, realize the experiment that experiment, mobile management, transfer table call treatment were landed and shut down to mobile platform started, comparatively Xing Xiang explanation the principal character of mobile communication.Mobile experimental box also is furnished with standard GSM/GPRS communication module, carries out speech and data communication by any user in software control realization and the real network.Can also finish the information source encoding and decoding on the experimental box, channel coding/decoding interweaves and experiment such as scrambler, modulation.
Student's platform: student's platform is a microcomputer, and it links to each other with experimental box by serial ports, links to each other with teacher's platform with other student's platforms by LAN (Local Area Network).Student's platform is that the student controls the platform that experimental box carries out corresponding experiment.Each experiment, the student enters the corresponding experiment interface of student's platform, and student's platform program can issue the control corresponding instruction to experimental box, the configuration relevant parameters, thus make experimental box carry out the preparation of corresponding experiment.The part result of experiment also will be sent on student's platform by experimental box by serial ports, and student's platform can clearerly be seen the part result of experiment by the interface.The concrete function of student's platform in each experiment is referring to the teachings of each experiment.In system experimentation, the effect of student's platform is very many, comprises following several respects: the effect of (1) mobile phone interface: buttons such as the start that exists on the general mobile phone, dialing, on-hook, shutdown will be arranged on student's platform.The student presses corresponding button, and student's platform is translated into corresponding message with these actions and sent to experimental box, and the MS of experimental box and BS begin corresponding signalling interactive process.(2) effect of signalling analysis and demonstration: in order to allow the student understand the signaling procedure between each functional unit in the GSM network.Signaling between MS, BS and the MSC all will be shown on student's platform.Therefore MS and BS receive that whenever a message all will be to the report of student's platform on the experimental box, and student's platform shows on the interface.At this moment, student's platform has just served as the effect of Signaling Analyzer in the reality.(3) effect of part MSC/VLR: student's platform also will be finished the function of part MSC/VLR in calling out control.Set up in the process with the mobile communication of other experimental group, the signaling of calling out control need be sent to other student's platform by student's platform by internal network.(4) maintenance of each functional unit parameter and demonstration: in order to allow the student understand the influence of specific signaling procedure to each functional unit parameter, student's platform will be safeguarded four parameter lists: MS parameter list, BS parameter list, MSC/VLR parameter list, HLR parameter list.Before system experimentation began, these parameters of student's platform were issued by teacher's platform, these four tables of list initialization that student's platform utilizes teacher's platform to receive.And the partial parameters of MS parameter list, BS parameter list to be handed down to experimental box by serial ports.After the experiment beginning, these four parameter lists of student's platform can change with the signaling process.After some specific signaling procedures, the student can observe the situation of change of each parameter list by the interface of student's platform.To the maintenance of MSC/VLR parameter list, the function of VLR database in the real system that has been equivalent to student's Platform Implementation.
Teacher's control and monitor console: teacher's platform monitoring platform links to each other with all student's platforms by LAN (Local Area Network).The effect of teacher's control and monitor console has: the work of control student platform.In the system experimentation part, be responsible for issuing of parameter lists such as HLR, MS.To safeguard a parameter list database on teacher's control and monitor console, after the experiment beginning, student's platform will be visited this database and be obtained the parameter list relevant with this student platform.To the maintenance of HLR parameter list, the function of HLR database in the real system that has been equivalent to teacher's Platform Implementation.Teacher's control and monitor console adopts microcomputer.
Small switch: the effect of switching equipment is to finish two Speech Communications between the MS.In the experiment of transfer table calling procedure, caller and called between after Signalling exchange finishes, switching equipment is finished continuing of speech between two student's platforms.In actual mobile communication system, speech and signaling except between BS and the MS by the wireless channel transmission, remainder all transmits by wire message way.Carry out voice connection with Private Branch Exchange PBX and simulated in the actual mobile communication system voice signal in the transmission of wireline side: the called BS of caller BS-caller MSC-called MS C-.
With reference to accompanying drawing 2 is the experimental box electronic schematic of mobile communication experimental system, and it has the portable terminal part, base station portion, and central controller, special experiment module and gsm wireless MODEM module constitute, being constructed as follows of each module:
(1) portable terminal part
Portable terminal mainly provides major technique and the functional module in the mobile communication, a lot of technology of using in the mobile communication for the experimenter is more clearly understood, and system is made up of a plurality of modules, promptly can carry out system experimentation, also can separately finish Individual testwas.
Portable terminal partly mainly contains:
1, audio frequency input/output interface (receiver and microphone)
2, DC level controller
3, PCM/ADPCM codec
4, LPC voice companding codec
5, channel coding/decoding, framing, modulating/demodulating DSP
6, channel forms device
7, wireless receiving and dispatching radio-frequency module
(2) base station portion
The circuit and the movable part of base station portion are roughly the same, main difference is in audio interface, the base station audio interface connects mobile switch, the voice-grade channel of this experimental box realizes that by telephone user interface and cable convertor many experimental boxs constitute mobile switching network, and signaling is by the Network Transmission between an experimental box central controller.
Base station portion mainly contains:
1, exchange interface
2, hands-free audio power amplifier
3, PCM/ADPCM codec
4, LPC voice companding codec
5, channel coding/decoding, framing, modulating/demodulating DSP
6, channel forms device
7, wireless receiving and dispatching radio-frequency module
(3) central controller
Central controller is that multipoint control unit is a core with single-chip microcomputer (CPU) MCU (Micro Controller Unit) Chinese, LCD display with 4 * 5 keyboards and 320 * 240, the three-way communication interface of RS232C link to each other with microcomputer (PC) and constitute the home base stations controller.Central controller is mainly finished the initialization to individual module, the setting of various experiments, the configuration of systematic parameter and signaling transmission.MCU can also be by the work of control GSM MODEM, with any user's communication experiment in the standard gsm network.
Central controller mainly contains:
1, single-chip microcomputer (CPU) AT89C55WD MCU control core
2, RS232C communication port
3,16C550 GSM MODEM communication interface
4, spi bus interface, ADPCM communication interface
5, DSP exchanges data and program load communication interface
6, LC4384 ISP data-interface (CPLD)
7, LCD display interface
8, keyboard interface
9, DSP HPI interface
10, other IO IO interface
(4) special experiment module
Special experiment module constitutes with scale programmable logic device (LVC384) and storer (RAM), can finish scrambler, interweave and experiment such as Error Correction of Coding the high speed processing method of realization hardware logic.The implementation method of showing the communication technology from another angle.
Main devices comprises:
1, LC4384 ISP programmable logic device (PLD)
2, data processing memory (62256)
3, ISP DLL (dynamic link library)
4, MCU communication interface
5, the IO of general use
(5) gsm wireless MODEM module
The gsm wireless MODEM of standard is in order to realize that wireless mobile experiment inserts the experiment of public network and establishes, when inserting effective SIM card, and can be under the control of MCU, receive and dispatch note with any wired and wireless user's conversation in the public network.
Critical piece has:
1, GSM MODEM module
2, SIM card
3, reset, power on and Audio Processing/change-over circuit
In the accompanying drawing 2, single-chip microcomputer (CPU) master controller (corresponding to inbond W78E) MCU (Micro Controller Unit Chinese is a multipoint control unit) is the core of control, comprises that also RS232C communication port, 6C550 GSM MODEM communication interface, spi bus ADPCM communication interface, DSP exchanges data and program load interfaces such as communication interface, LC4384 ISP data-interface (CPLD), LCD display interface, keyboard interface.When different working methods was selected by software by system, system linked to each other by the different interfaces chip different with system.When at the software (accompanying drawing 1 is seen at the interface) that it is suitable that student's platform is packed into, student's platform (PC) links to each other with the RS232C communication interface of experimental box by data line, when in the different experiment of student's platform selecting, can show this experiment content on 320 * 240 the LCD display.When carrying out information source coding, after the flow process of signal is encoded through PCM/ADPCM codec (MC145540) from the voice signal of microphone or outside input in the experimental box, mode with synchronization frame is exported, comprise and receive and send totally 6 signal wires (DX, XCLK, FSX, DR, RCLK FSR), can be connected with the TMS320C54XX family chip of TI at an easy rate.In this experimental box, that we select for use is TMS320VC5410.When selecting the channel coding/decoding experiment, MCU single-chip microcomputer (CPU) links to each other with ISP1016 channel coder/decoder and therefrom transfers program.When selecting the GSM experiment, MCU single-chip microcomputer (CPU) links to each other with gsm wireless MODEM module by 16C550 GSM MODEM communication interface; When selecting to use special experiment module, MCU single-chip microcomputer (CPU) links to each other with LATTICE4384 by the LC4384ISP data-interface.When selecting Channel Modulation demodulation experiment, MCU single-chip microcomputer (CPU) loads communication interface by DSP exchanges data and program and links to each other with DSP TMS320VC5410 exchanges data and program loading communication module, signal is modulated and carried out waveform in corresponding ports and observe, the signal that modulates just can be transmitted to the base station by wave point, the base station after receiving signal, signal separated be in harmonious proportion source decoding the most at last signal deliver to other experimental boxs by exchange interface among Fig. 2, thereby constitute a complete communication process.
Experiment content that the utility model comprises and experiment Introduction
(1) information source encoding and decoding experiment
The purpose of information source coding experiment is to allow the student understand the classification and all kinds of algorithm basic principle of current speech Coding Compression Algorithm.The information source encoding and decoding of experimental box have partly realized the plurality of information resources codec, mainly be divided into two big classes, one class is based on the pcm encoder (speed is 64Kbit/s) of waveform coding and adaptive prediction coder ADPCM, and (speed is 32kbit/s, 16kbit/s), the another kind of AMBE coding that is based on parameter coding.
(1) PCM and ADPCM coding
It mainly is experiment about waveform coding.Can allow on the one hand the student by adjusting potentiometer, change the DC level of input PCM encoder, watch waveform after direct current signal passes through pcm encoder by oscillograph then, thereby understand the principle that A leads 13 broken line pcm encoders in depth; On the other hand, can also allow the student select coded system (64kb/s PCM, 32kb/s ADPCM, 16kb/s ADPCM),, acoustically contrast the voice quality of the waveform coding under the different rates from subjectivity by voice recording and time-delay playback.
(2) improved many band excitation algorithms (AMBE)
The AMBE algorithm is a kind of speech compression coding algorithm of hybrid coding.In this experiment, the student can dispose different compress speech speed (2.0kb/s～9.6kb/s) by test platform, by voice recording, time-delay playback and clock waveform relation, acoustically observe under the different rates variation of voice quality and the relation of speed from subjectivity.
(2) channel coding/decoding experiment
The fundamental purpose of chnnel coding experiment is to allow the student understand the ultimate principle of Error Control and chnnel coding.Can understand several error coding principle and error-correcting performances thereof commonly used by experiment in depth.Chnnel coding mainly comprises with decoding experiment (corresponding to 3,4,5,6 experiments in the experiment content): the codec of linear block codes+interweave, reflected code, convolutional code and scrambler.
(1) block code+interweave with separate block code+deinterleaving
This experiment is example with (7,4) Hamming code in conjunction with (8 * 7) interleaver, on the one hand, demonstrates the effect that interweaves in entangling the channel burst mistake with software.On the other hand, also to have disposed a CPLD with LatticeMACH 4384 be the daughter board of acp chip to this experimental box.By this daughter board, can use Verilog HDL language compilation program, after the adaptive success, program is downloaded to CPLD, realize appeal block code+interweave and separate block code+deinterleaving function with the method for hardware.More in depth the method that realizes of deinterleaving and group coding.
(2) Code And Decode of reflected code
This experiment is an example with (15,7) systemic circulation sign indicating number, on the one hand, demonstrates the error-correcting performance of this reflected code with software.On the other hand, also to have disposed a CPLD with Lattice MACH 4384 be the daughter board of acp chip to this experimental box.By this daughter board, can use Verilog HDL language compilation program, after the adaptive success, program is downloaded to CPLD, with method realization appeal (15,7) systemic circulation code function of hardware.More in depth the implementation method of reflected code Code And Decode.
(3) coding of convolutional code and decoding (Viterbi decoding)
This experiment is an example with (2,1,2) convolutional code, on the one hand, demonstrates the error-correcting performance of this convolutional code with software.On the other hand, also to have disposed a CPLD with Lattice MACH 4384 be the daughter board of acp chip to this experimental box.By this daughter board, can use Verilog HDL language compilation program, after the adaptive success, program is downloaded to CPLD, realize the coding and decoding function of appeal convolutional code with the method for hardware.More in depth understand the implementation method of convolutional encoding and Viterbi decoding.
(4) scrambler and descrambling
The m sequence that this experiment realizes with 8 bit linear shift registers is a scrambler sequence, on the one hand, and with the effect of software demonstration scrambler.On the other hand, also to have disposed a CPLD with Lattice MACH 4384 be the daughter board of acp chip to this experimental box.By this daughter board, can use Verilog HDL language compilation program, after the adaptive success, program is downloaded to CPLD, realize appeal scrambler and descrambling code function with the method for hardware, more in depth the method that realizes of scrambler.
(3) modulation experiment
This part comprises GMSK modulation, QPSK modulation and band spectrum modulation/separate three experiments of spread spectrum.This is a used main flow modulation system in the present mobile communication system.
(1) GMSK modulation, demodulation experiment
Introduce 2 kinds of modes of GMSK+FM modulating/demodulating and GMSK orthogonal modulation/demodulation, realized GMSK orthogonal modulation/demodulation.Adopted the differential ference spiral mode, realized processes such as sign synchronization, differential ference spiral, symbol judgement, and, vividly reproduced the signal waveform situation of change of each link of modulation by the DAC on virtual oscilloscope and the experimental box.
(2) QPSK modulation, demodulation experiment
QPSK modulation and demodulation principle, carrier synchronization mechanism, sign synchronization mechanism and difference encoding and decoding principle have been introduced.By the DAC on virtual oscilloscope and the experimental box, vividly reproduced the signal waveform situation of change of each link of modulation.
(4) system experimentation
The purpose of system experimentation is to allow the student grasp the frame structure and the forming process thereof of speech and signaling; Grasp basic calling and the managing signaling flow process of GSM, comprise start IMSI attaching process; MS (transfer table) caller, called signaling procedure; Position updating process in the mobile management.In order to make the student clearer as to grasp signaling process, the reciprocal process of signaling has two kinds of patterns, normal mode of operation and single-step mode.Under normal mode of operation, when MS and BS receive certain incident, signalling interactive process carries out with operate as normal speed, and speed is very fast; Under single-step mode, the reciprocal process speed of signaling is slower, presses the mutual of " next step " key control signaling by the student, thereby makes student's control experiment on one side guiding book study signaling content, Yi Bian observe signalling interactive process.In addition, by experiment the student can also grasp that transfer table is started shooting, during action such as shutdown, position renewal (roaming), the change situation of system's associated databases content.The content of each parameter will show on student's platform interface.There are five experiments this part.
(1) the GSM mobile platform started networks and the shutdown experiment
The student A, can know to such an extent that see transfer table after start in mobile station network access and shutdown experiment, and MS is with the signalling interactive process between the network; After B, the start, in the data list of MSC/VLR for the change of this MS parameter.C, press closing key after, the change situation of the reciprocal process of signaling and MSC/VLR parameter list between MS and the network.
(2) mobile management experiment
GSM mobile management experiment mainly is that simulation MS carries out position renewal in two kinds of position updating process: MSC/VLR, strides the MSC/VLR position renewal.By this experiment, when the student on the one hand can observe MS and carries out position renewal from the interface, the signalling interactive process between MS, BS, these entities of MSC/VLR, HLR.On the other hand, also simulated the database information of MS, MSC/VLR, HLR inside on student's platform, can allow the student see, after the position renewal, in each entity to the change of this MS record, thereby realize Position Tracking to MS.
(3) MO mobile origination experiment
In this experiment, the student will import called number and press the transmission key on student's platform, the experiment of beginning MO mobile origination.With the cooperation of called student's platform, in the time of will seeing MO mobile origination in student's platform interface, the signalling interactive process between MS and BS, the MSC.After reciprocal process finished, caller student platform and called student's platform just can be conversed.Behind the end of conversation, on the interface, also will show the signalling interactive process in the speech dispose procedure.(experiment method has single-step operation and two kinds of forms of normal execution).
In addition, by with called cooperation, can also observe:
A, called number do not exist.
B, called the start or Called Busy.
C, calledly do not receive calls for a long time
Signalling interactive process when taking place etc. unscheduled event.
(4) the called experiment of transfer table
In this experiment, the MS on student's platform is as called MS, and the prerequisite of experiment is that the MS master on other student's platform exhales this student's platform.To show when transfer table is called signalling interactive process between MS and BS, the MSC on student's platform interface.After reciprocal process finished, caller student platform and called student's platform just can be conversed.Behind the end of conversation, on the interface, also will show the signalling interactive process in the speech dispose procedure.
(5) gsm protocol frame structure experiment
The experiment of gsm protocol frame structure is divided into two classes: the experiment of data frame structure experiment and signaling frame structure.In the experiment of data frame structure, will show how speech data encodes to the student, piecemeal, interweave, finally form the process of physical layer bursts, the state of data was how after each step process was finished.In the experiment of signaling frame structure, we are example with the Set up message that call control layer (CC layer) produces, illustrated processing that how signaling to pass through signaling L3, L2 (data link layer), L1 (Physical layer) by signaling message become the data link layer frame, again by chnnel coding, interweave, finally become the process of physical layer bursts.
(5) 900MHz GSM mobile handset system experimentation
Realize the login, caller of gsm system, the functions such as transmitting-receiving of called and short message.This experiment during experiment, needs SIM card owing to adopted the mobile network of operator.
As way of extensive experimentation, a kind of transparent mode is provided, can on command window, import various AT orders, the gsm module that is adopted is carried out various operations, comprise call (as incoming call, exhalation, ring indication, off-hook/on-hook, caller ID indication, volume adjusting etc.), short message (sending SMS message, come message to indicate, read SMS message, delete short message, short message list, TEXT/PDU mode switch etc.) and other commonly used commands, amount to more than 100.Certainly also can realize the calling of non-transparent mode and the function of sending short messages.
Claims (4)
1. the mobile communication experimental system is characterized in that comprising experimental box, student's platform, teacher's control and monitor console, small branch exchange; Experimental box comprises portable terminal part, base station portion, central controller, special experiment module and gsm wireless MODEM module; Portable terminal comprises that partly audio frequency input/output interface, DC level controller, PCM/ADPCM codec, LPC voice companding codec, channel coder/decoder, framing, modulator/demodulator (DSP), channel form device, wireless receiving and dispatching radio-frequency module; Base station portion comprises that exchange interface, hands-free audio amplifirer, PCM/ADPCM codec, LPC voice companding codec, channel coder/decoder, framing, modulator/demodulator (DSP), channel form device, wireless receiving and dispatching radio-frequency module; Central controller comprises that single-chip microcomputer (CPU), RS232C communication port, GSM MODEM communication interface, spi bus interface, ADPCM communication interface, DSP exchanges data and program load communication interface, LC4384 ISP data-interface (CPLD), LCD display interface, keyboard interface, DSP HPI interface and IO IO interface; Special experiment module comprises ISP programmable logic device (PLD), data processing memory (62256), ISP DLL (dynamic link library), MCU communication interface, IO interface; Gsm wireless MODEM module comprises GSM MODEM module, SIM card, resets, powers on and Audio Processing/change-over circuit; Mobile experimental box is provided with some, be equipped with microcomputer (PC) system and software, simulated mobile switching network by LAN (Local Area Network) and telephone exchange, student's platform links to each other with experimental box by serial ports, links to each other with teacher's control and monitor console with other student's platforms by LAN (Local Area Network); Teacher's control and monitor console links to each other with all student's platforms by LAN (Local Area Network).
2. mobile communication experimental system according to claim 1, it is characterized in that central controller is that multipoint control unit is a core with single-chip microcomputer (CPU), LCD display with 4X5 keyboard and 320X240, the three-way communication interface of RS232C link to each other with microcomputer (PC) and constitute the home base stations controller.
3. mobile communication experimental system according to claim 1 is characterized in that student's platform adopts microcomputer.
4. mobile communication experimental system according to claim 1 is characterized in that teacher's control and monitor console adopts microcomputer.
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| CNU2007200368856U CN201035821Y (en) | 2007-05-09 | 2007-05-09 | Mobile communication experiment system |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103198734A (en) * | 2012-01-06 | 2013-07-10 | 苏州市职业大学 | Signal synchronization PCM coding and decoding experiment system |
| CN103973686A (en) * | 2014-05-08 | 2014-08-06 | 重庆邮电大学 | Mobile communication system test platform based on computer software virtualization technology |
| CN104794952A (en) * | 2015-05-14 | 2015-07-22 | 北京交通大学 | Teaching experiment system and teaching experiment method of transponder system |
| CN106373458A (en) * | 2016-11-15 | 2017-02-01 | 湖北大学 | Software radio technology-based communication experiment device and experiment method therefor |
| CN107564382A (en) * | 2017-09-14 | 2018-01-09 | 广东工业大学 | A kind of communication theory experiment method, system and its collocation method |
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2007
- 2007-05-09 CN CNU2007200368856U patent/CN201035821Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103198734A (en) * | 2012-01-06 | 2013-07-10 | 苏州市职业大学 | Signal synchronization PCM coding and decoding experiment system |
| CN103973686A (en) * | 2014-05-08 | 2014-08-06 | 重庆邮电大学 | Mobile communication system test platform based on computer software virtualization technology |
| CN104794952A (en) * | 2015-05-14 | 2015-07-22 | 北京交通大学 | Teaching experiment system and teaching experiment method of transponder system |
| CN106373458A (en) * | 2016-11-15 | 2017-02-01 | 湖北大学 | Software radio technology-based communication experiment device and experiment method therefor |
| CN107564382A (en) * | 2017-09-14 | 2018-01-09 | 广东工业大学 | A kind of communication theory experiment method, system and its collocation method |
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