CN1385027A

CN1385027A - Wireless modem

Info

Publication number: CN1385027A
Application number: CN00815058A
Authority: CN
Inventors: P·P·蒂纳洪; T·普朗蒂普
Original assignee: RCA Licensing Corp
Current assignee: Thomson Licensing SAS; RCA Licensing Corp
Priority date: 1999-10-29
Filing date: 2000-10-30
Publication date: 2002-12-11
Anticipated expiration: 2020-10-30
Also published as: KR20020044575A; JP2003535489A; CN1241432C; EP1230786A1; WO2001033824A1; AU1246901A

Abstract

A wireless modem system having two devices, wherein each device can transmit and receive data via a plurality of RF channels, the data being applied to the channels in sequence. In one embodiment, a first device may be used for coupling to a computer for receiving data from the computer. The first device encodes the received data from the computer and transmits the received data using a digital wireless transmission format to a second device. The second device receives the transmitted data from the first device in the digital wireless transmission format and further processing it into an analog format for transmission over a wired telephone network.

Description

Radio modem

Technical field

The present invention relates to radio communication, more specifically, the present invention relates to a kind of wireless modem system, it allows a computer need not physically to depend on teleprocessing data under the situation of telephone handset communication port.The integrality of the communication that sends and/or receive with protection is operated by this system on this modulator-demodulator.

Background technology

Modulator-demodulator worldwide extensive use make can mutual communication such as the electronic equipment of computer.Typically, modulator-demodulator is coupled to a communication jack with a computer, utilizes a lead or cable to send and/or received communication by this socket.But, need a modulator-demodulator physically to be coupled to a jack and limited the ability that when the equipment of modulator-demodulator is enabled in use, moves freely.In response, radio modem is designed so that the user can send and/or receive communicating by letter from laptop computer and other electronic equipment, and be connected to a jack, thereby make computer can be used to not consider its communication about the position of a jack with need not computer physics.But, traditional radio modem has a serious defective.Clearly, use the integrality of the communication of the transmission of this equipment and/or reception to fail through regular meeting.Therefore, an object of the present invention is to provide the radio modem of the bigger communication integrity of a kind of supply.

Description of drawings

Fig. 1 represents the block diagram according to an example embodiment of wireless modem system of the present invention.

Fig. 2 represent to be used for as shown in Figure 1 equipment power up initialized flow chart.

Flow chart among Fig. 3 is used to represent a continuous operation circulation RL, and it is carried out, and the aligning position monitors and the reception data buffer supervision receives in equipment shown in Figure 1.

Fig. 4 represents to be used for the flow chart that the data by equipment shown in Figure 1 send.

Fig. 5 represents to be used for the flow chart of the UART/ modulator-demodulator Interrupt Process of being undertaken by equipment shown in Figure 1.

Fig. 6 represents the flow chart of the Data Receiving of being undertaken by equipment shown in Figure 1.

Fig. 7 represents to be used for the flow chart that the channel tracking timer of the nothing branch group of received of being undertaken by equipment shown in Figure 1 interrupts.

Fig. 8 represents to be used for the schematic diagram of a primary processor of equipment as shown in Figure 1, and comprises SST (spread spectrum) processor and a SRAM who is used for equipment as shown in Figure 1.

Fig. 9 represents to be used for the schematic diagram of UART, light-emitting diode indicating device and the RS-232 interface of equipment as shown in Figure 1.

Figure 10 represents to be used for the schematic diagram of the RF transceiver of equipment as shown in Figure 1.

Figure 11 represents to be used for the schematic diagram of the power supply of equipment as shown in Figure 1.

The circuit diagram of Figure 12 and 13 expressions equipment as shown in Figure 1.

Summary of the invention

According to the present invention, a kind of wireless modem system is provided, it is automatic that its use provides The RF signal detection is protected logical in order to be locked in selected channel after a handshake procedure The integrality of letter. Particularly, be used for the Data Modulation reconciliation being transferred to and being used for from computer Article one, the modem feature that transmits on the analog of telephone line only is present in the long distance wireless modulation /demodulation In the device.

Embodiment

The ISM band (902-928MHz) that is used for radio modem (WM) operation of equipment wireless modem system and that be called radio modem jack (WMJ) or RF link at for example 900Mz described herein.Wireless modem system for example comprises an elementary cell 1000 and wireless remote modulator-demod 10001 as shown in Figure 1.These two unit can both transmit and receive data simultaneously/fax.Unique difference is that elementary cell 1000 does not need " modulator-demodulator " function (for example 18 ') and relevant phone to handle (for example 20 '), this is because as shown in Figure 1, and data are modulated and be demodulated to the analog signal that sends and receive in remote wireless unit 1001.

The design of system is preferably based on Direct swquence spread spectrum (DSSS) technology, and it also provides in radio-frequency spectrum, especially the maximum safety of the data of launching in the 900MHz scope.At present, the largest data transfer that is used for WMJ can reach 115Kbps (via the radio frequency link), and it is in the much higher speed that is connected with the hard wire modulator-demodulator of a routine when comparing.WMJ can be used for Internet service and connect, and the data that send/receive faxes data and be used to transmit other type.All transmission all are the forms with the SST digital encryption.

Therefore, the present invention allows the support of RF link to have the data rate that reaches 115kbps of EDC error detection and correction.It and V.90/56K Flexible High Speed Paging (flex) modem standard compatibility, thus allow it can be used for many existing Internet service suppliers' business.As described below, system provides automatic RF input and locks onto on the selected channel in two unit (after the handshake procedure that a quilt identifies).

Because elementary cell 1000 comprises a serial port, so system not only can insert the traditional modem of computer network by telephone wire as one, can also be used for that remote printer is shared, the network between two PC terminals connects.System can also support the hyper terminal transfer of data.

In addition, because modulation signal is with digital form,, replace 100 milliwatts in the analog-modulated type so FCC allows to equal the maximum transmission power of (1) watt.The better scope that this will allow transmission reaches 300 feet the scope (or better) under the residential environment condition usually.

Now, personal computer (PC) and the Internet are worldwide more and more universal.Most consumers can use the common connection by a routine call jack to insert the Internet.Unfortunately, most of dwelling house family has only jack on one or two phone wall in whole room.Therefore, for most of people, it is problematic in the position of jack a PC being installed on away from a phone wall.

Use WMJ, consumer can for example insert the Internet or transmission/receive faxes, perhaps transfer files between whole room two PC Anywhere.Data (signal) can be by the digital form of signal encryption.Radio frequency (RF) signal can be in the scope of 900MHz; From 902-928MHz.The WMJ design is based on the digital spread spectrum technology.Therefore, WMJ can go up in the distance (about 300 foot) bigger than any 900MHz equipment of the signal that sends a conventional simulation modulation format and send and received signal.Compare with the equipment with analog-modulated form of the power output that only is allowed to 100 milliwatts, any equipment that the part 15 of FCC rule allows to have digital modulation formats has 1 watt RF power output.

The block diagram that Fig. 1 is used for elementary cell RF link is discussed.Integrated operation at first sends data conditions for RF link wherein from a unshowned PC and is described, and then, receives data conditions for RF link wherein from a unshowned RF link transmitters and is described.Here should point out an elementary cell 1000 and a remote unit or expand unique difference between 1001 and be that remote unit has the modem feature 18 ' of an embedding extraly and is used for the additional circuit 20 ' of a RJ-11 jack interface to telephone network once more.Therefore, for fear of redundancy, below describe and mainly concentrate on elementary cell.

DCE side mouth 2 is coupled to the PC computer, and this computer is not shown and the serial digital data that is received is sent to the interface 4 that a voltage level with each bit is adjusted into a standard value.UART 6 is converted into parallel data with serial data, and processor 14 one of structure have the packet of an align bit, guiding byte, message byte and an afterbody byte.Then, this grouping is stored in a Tx buffering area among the SRAM 8.SST 10 seeks in the RF modules 12 the not channel of usefulness, sense data in the Tx buffering area from SRAM 8, and these data are offered the channel of RF module 12 with repetitive sequence.Everything is all by MCU 14 controls, and the various operational scenario of LED indicating device 16 indications.

When the RF of Fig. 1 link will be when external RF link receives data, SST is with regard to the channel of scan module 12, and the data that therefrom receive are sent to a unshowned rx buffering district in SRAM 8 by SST.Under the control of MCU 14, data in the packet are re-constructed and are sent to UART 6, wherein parallel data is converted into serial bit stream, and these bits were carried out the voltage adjustment in interface 4 before being applied to the DCE side mouth 2 that is coupled to another PC.

Initialization

Flow chart among Fig. 2 is discussed now, and this figure has illustrated when shown in 22, when power supply is opened, has perhaps appeared at an elementary cell or appear at a situation in the expanding element.If the indication of the test in the SRAM 8 of unit does not have more situation to occur owing to correctly not operating SRAM 8 defectively, then undo.Whether at rhombus decision block (hereinafter being called " decision block ") 26, judging has something to be coupled to DCE side mouth 2.If something coupling is arranged, PC for example, and if it be an elementary cell BU, as shown in Figure 1, then modulator-demodulator 18 is left in the basket, and BU must be set to the principal and subordinate shown in 28.The main bit of DIPSW 1 as shown in Figure 8 is tested.If this switch connection (perhaps be arranged on ' upwards (up) ' position), then a corresponding status of a sovereign of OPSTAT (mode of operation) register is set up.Otherwise this position is eliminated.A common expanding element (EU) always is set to master unit (starting the unit of transmission), and elementary cell (BU) is set to from the unit (unit listen mode always).For the application that does not need modem feature, can use two BU.In this case, a BU must be set to ' main ', and another is set to ' from '.If desired, then BU (serial port is selecteed) can also be set to main, and another BU (serial port is selecteed) or expanding element EU be set to from.

If shown in decision block 30, carried out main a setting, then indicated as 32, the channel of RF module 12 is scanned.100 milliseconds of the RSSI of the RF channel that master unit monitors is independent (received signal strength indicator).All ten RF channels (0-9) are scanned.Then, select a channel the most static.Afterwards, whether master unit monitors has any transmission activity on channel.If no, then this channel is selected for transmission.The timer of MCU 14 is used to the scan channel timer by a chscan_to Interrupt Service Routine processing.

After channel was selected, shown in 34, the nothing grouping was received timer and is activated.This forces and itself enters the link establishment process when timer expiration.Then, follow the process of Fig. 7.Then, 36, the appropriate register of rx buffering district and HDx (sending or receive operator scheme) is set.At this point, the unit enters as shown in Figure 3 running time and circulates RL.

With reference to decision block 30, main if the unit is not set to, and therefore be from, then it will be in 38 baud rates that UART 6 is set, and start 40 and to follow the tracks of timers.This function is only carried out from the unit at one, and comprises the RF channel that scans a master unit.As an example, each channel is scanned 20 milliseconds.

With reference to decision block 26,, then check and see whether modulator-demodulator 18 is mounted 42 if DTR does not activate.If, then the unit be set to from, and make modulator-demodulator Rx interrupt 44, mean and do not carry out and the communicating by letter of modulator-demodulator, and proceed to piece 36.If not, then be provided with from enabling UART Rx and interrupt, and routine turns back to piece 28 46.

Circulation running time

Finished in Fig. 2 and set up after the routine, radio link enters continued operation circulation running time as shown in Figure 3.At decision block 48, whether inquiry has received one and has aimed at byte.Because byte is not aimed at by the end a data grouping, so its shortage means that packet is received.If it is received, then enter a RBUF in the service routine, wherein data be stored among the SRAM 8 the Tx buffering area or in the rx buffering district.Till this partial circulating is repeated until that not aiming at byte is received.If in 48 indications of not aiming at byte, then check to see whether a RF link has been declared connection (declare up) 50, mean that finishing one shakes hands, so that this RF link is ready to send data.If not, then underway not use, and process turns back to the beginning of circulation.But,, then in the 52 Rx data buffer zones of judging at SRAM 8, whether any data are arranged if stated that 50 a RF link connects.If have, then indicated as 54, according to which kind of action type takes place, it is sent to UART 6 or sends to modulator-demodulator 18.If have only DTR activation (for example PC is connected to port does not have ready) and link to exist ' connection (up) ' state, the unit just is forwarded to UART 6 with data from the receiver buffering area for elementary cell BU.Modem feature is only relevant with BU.Write/read corresponding to writing to the fifo buffer of UART 6 or modulator-demodulator/reading to UART 6 or modulator-demodulator from the fifo buffer of UART 6 or modulator-demodulator from UART 6 or modulator-demodulator.After data were sent out, process turned back to the beginning of circulation.

Transmission

As shown in Figure 4, carry out transfer of data since 56.At first, any data in the tx buffering district among the transmission SRAM 8.At first, check whether receive a retransmit bit that repeats to transmit as request as shown in Figure 7 58.If then 60, the pointer in the tx buffering district among the SRAM 8 is resumed, but if not, then 62, data are read from the Tx data buffer zone.64, the Tx buffer pointer is saved, and shown in 66, construction data grouping in UART 6.Data are copied to the data division of packet buffer (register of MCU) by the transmission buffering area from SRAM 8.Byte number during data are divided into groups is that 0 (zero) is to 72.A grouping envelope (envelope) is added.This envelope comprise packets headers byte, controlling links byte, block length (from the beginning byte count to verification and last byte) and channel number/unit marks byte.

68, routine computes and in the end the end of data byte add 16 bit Fu Laiche (fletcher) verifications and.15 prefix bytes (0x00) and 2 aligning bytes (0x80) are arranged before the grouping of a transmission.Five afterbody bytes (0xff) are added to the end of transmitted in packets.

70, check whether the RF link is set to a master unit by a hand switch.If then 72, the nothing grouping is received timer and is activated, and follows the process that also will describe as shown in Figure 7 subsequently.

Flowcharting among Fig. 5 is used for the step of UART/ modulator-demodulator Interrupt Process service 102, and wherein 104, data are read from UART 6 or modulator-demodulator Rx FIFO.106, be empty up to buffering area, be written into the Tx data buffer zone then, and 108, the transmission that turns back to Fig. 4 begins 56.

Receive

Fig. 6 is discussed, and in 74 beginnings, routine monitors two continuous aligning bytes (0x80).These bytes may correctly not aimed at.The unit reads and aims at seven bytes of the data (6 to 78) in the grouping.If block length surpasses 6 (but being not more than 78), then the unit reads remainder bytes from SST, and stores in the packet buffer (register of MCU).If be received according to decision block 76, one stature bytes, then shown in 78, data are read among the SST Rx FIFO from SRAM 8.At decision block 80, check the validity of packet.At decision block 82, check whether the address of data is the addresses that receive the RF link.This is the program function among the MCV8 of two unit, is used to check that the link that is used to divide into groups connects or whether link-down (down) is set up, and is used for transmission from the unit so that prepare to advocate peace.This stops adjacent transmission of acquisition.At piece 84, according to the lamp of indicating the RF link to be ready to receive described link statement is connected, and check 86 whether master/slave switch is arranged on from the position.If then 88, the user can utilize the combination of switch or by software baud rate is set.Usually, baud rate is set to maximum.See Fig. 7,90, the nothing grouping is received timer and is activated, and 92, sets up a link establishment grouping in MCU 14, with the more multidata of request from buffering area.If it is a master unit for decision block 86 indications, then at piece 87, data are sent out, and enter circulation running time of Fig. 3.

Decision block 82 is discussed once more, is indicated not when being received when a link establishment grouping, 94, if packet is received in turn, then it is written in the Rx data buffer zone of SRAM 8, and sends to 100.Turn back to circulation running time of Fig. 3 from any one NO indication process that makes of

decision block

76,80 and 94.

Fig. 7 represent to be used to advocate peace from the nothing grouping be received/channel tracking timer interrupt handling program.If determined as decision block 110, two data links are established, and shake hands if promptly carried out one between them, then read a time-out count device 112.If there is a transmission to interrupt, then the time-out count device begins counting.When each packet was transmitted, the time-out count device brought into operation, and when the last or afterbody byte of a message was passed through, clock was set up back 0.Therefore, if at decision block 114, counter is not 0, means that then packet is not sent fully, and in this case, a retransmit bit is sent out back transmitter.This is the retransmit bit of indication in the decision block 58 in Fig. 4 that explanation sends.After this, process turns back to decision block 110.

By advocating peace from the unit maintenance and using a time-out count device to state link-down.The value of counter is different for advocating peace from the unit, is respectively 10 and 1 for advocating peace from the unit promptly.In addition, the value of NPR (not having grouping is received) timer all is different from the unit for advocating peace, and is respectively 500 milliseconds and 1000 milliseconds for advocating peace from the unit promptly.

For master unit, if do not receive the valid data since the unit to divide into groups within after sending a data grouping 50 milliseconds, then master unit resends this packet.Ten statement link-downs that expire continuously of NPR timer, and master unit reenters channel scan procedure.When a valid data grouping was received, counter was just reinstalled.The value of NPR should enough be dealt with the longest packet.From 6 to 78 bytes of the length of packet change, except preposition, aligning and tail bits.

Because always in listen mode, promptly never the log-on data grouping sends from the unit, so as long as a NPR expiration just is enough to illustrate link-down.The value of NPR is selected attempts to receive since then from the total time of the response of unit, promptly 10 * 50 milliseconds by resending packet to cover master unit.After the statement link-down, " play the part of death " from the unit other 1000 milliseconds, to guarantee master unit statement link-down and to restart link establishment.Notice that aforementioned mechanism is not used in the link establishment process, this is the response that receives since the unit owing to short of, and then master unit just will constantly send link establishment.

But,, then advocate peace and all finish, but they will rest in the handshake mode, till judging that at decision block 116 this is a main equipment or slave unit from the transmission of unit if turned back to 0 at decision block 114 indication time-out count devices.If main equipment, then shown in the

piece

32 and 34 of Fig. 2,117, SST 10 scanning channels.

On the other hand, if decision block 116 indication RF links are not master units, and be therefore from the unit, then at piece 126, master unit is apprised of the statement link-down, promptly state for the transmission of advocating peace from the unit and finish, but they maintains in the handshake mode.128, find available channel.At piece 124, these are used to the DSS pattern, and one of them is followed the tracks of timer and is activated, so that send data in turn in available channel.

If in the indication of decision block 110 is that link between the RF unit is not also correctly set up, promptly link does not connect.If judge that at decision block 120 it is not a master unit, promptly it is from the unit, and then piece 122 finds available channel in the mode identical with piece 124.If the indication at decision block 120 is that it is a master unit, then sends a data grouping, and be received timer in nothing grouping of piece 128 startups at piece 126.

In the process of the schematic diagram that Fig. 8-13 is discussed, should be appreciated that the example that the particular microchip of appointment just can be used.They can be indicated with the abbreviation that they only get initial by " U " numbering with them.

Fig. 8 is that wherein MCU 140 is U ₄The schematic diagram of primary processor.Be used for pattern U as the piece 24 test SRAM 8 of Fig. 2 ₆And the answer U of SRAM ₆Transmit by data path 130.Being used to provide switch, baud rate and a unit of RF chain line is to lead or indicate 132 from quilt, and is coupled to MCU U by buffering area 134 and data path ₄Pin one 38.Oscillator 138 is the RF that SST chip 141 is provided to the GFSK transceiver 142 of Figure 10 by lead 144, and it is provided to the RF channel of the antenna 145 of Figure 10.Every connection attempt to be described, this be because believe those skilled in the art according to shown and describe how to put into practice content of the present invention and can know every connection.

Schematic diagram among Fig. 9 is represented as U ₁₀UART and handle 4 in 146 RS-232 interface.By 148 expression DCE communication port 2, and be used to indicate the LED of various operating conditions in 150 expressions.

Schematic diagram among Figure 11 is represented the power supply 154 that is used for the power supply 152 of all elementary cells as shown in Figure 1 and is used for expanding element.

Schematic diagram among Figure 12 and 13 represents to allow the modulator-demodulator 18 of expanding element and internet communication.It comprises U ₁₈With U ₁₈, and be useful on the plug 154 that is coupled to telephone wire.

A large amount of modification of the present invention and alternate embodiment are conspicuous for the those skilled in the art who has considered foregoing description.Therefore, this description just is used to illustrate and is used to instruct those skilled in the art about carrying out best mode of the present invention.Under the condition that does not depart from spirit of the present invention, can make amendment to the details of embodiment, unique use of all modifications within the scope of the appended claims is retained.

Claims

1. a wireless modem system comprises first and second equipment, wherein:

First equipment comprises:

Be used to be coupled to a computer, with device from this computer receiving data;

Be used for digital coding that is received and the device that uses a digital wireless transmission form that the data that received are sent; And

Second equipment comprises:

Device is used to receive the data that send with digital radio transmission form from first equipment, and further it is treated as analog format, is used for sending on the net at telephone.

2. the system of claim 1, the data that wherein received are used digital radio to send form and send to second equipment in available channel on the selecteed channel.

3. the system of claim 1, wherein second equipment comprises a modulator-demodulator that is used for further the transmission data processing that is received being become analog format.

4. the system of claim 3, wherein modulator-demodulator receive and demodulation from the analog signal of cable telephone network.

5. wireless modem system that comprises first and second equipment, described each equipment has:

A port that is used to receive serial data;

The serial data that is used for being applied to its any side is converted into the parallel data that is coupled to described port;

A transmitter buffering area;

A receiver buffering area;

Be used for from control device occurring from the data creation packet of described chromacoder;

Be used for described packet is coupled to the device of described transmitter buffering area;

Transceiver with a plurality of channels;

Be used for the data of described transmitter buffering area are applied to repetitive sequence the device of the selected channel of described transceiver; And

Be used for the packet that described transceiver receives is stored into the device of described receiver buffering area, described control device is suitable for the grouping in the described receiver buffering area is sent to described chromacoder.

6. according to the modulator-demodulator of claim 5, comprise also being used to scan the device of the channel of described transceiver that described channel is used as described selecteed channel with the identification clear channel.

7. according to the modulator-demodulator of claim 4, also comprise:

In each of described first and second equipment, be used for selectively determining the hand-guided device of its address;

In each of described first and second equipment, be used for determining the hand-guided device of other RF device address;

In described first and second equipment, be used for the address of its address and other equipment is write the device of its transmitter buffering area;

Device in described first and second equipment, it is used for institute's receiver address for other equipment is compared with the known address that is used for other RF equipment in response to the reception of itself address; And

If it is identical to be used for the address of being compared, then carry out further communicating devices.