Wavecom GX64 GSM 27.010 Multiplexer Feature, Application Note

Page 1: ...GX64 APPLICATION NOTE GSM 27 010 Multiplexer Feature Reference WI_DEV_Gx64_APN_006 Revision 001 Date 2007 01 30 ...

Page 2: ...ed or registered trademarks of their respective owners Copyright This manual is copyrighted by WAVECOM with all rights reserved No part of this manual may be reproduced in any form without the prior written permission of WAVECOM No patent liability is assumed with respect to the use of the information contained herein No Warranty WAVECOM publishes this manual without making any warranty as to the ...

Page 3: ...éalable 3 1 7 BENEFITS OF MUX 3 2 7 INTENDED AUDIENCE 4 Use Case Examples 8 5 GR GS64 27 010 MUX Implementation 10 5 1 10 BASIC OPTION 5 2 10 CONVERGENCE LAYER TYPE 1 5 3 10 NUMBER OF CHANNELS 5 4 11 PARAMETER NEGOTIATION 5 5 11 MODEM STATUS COMMAND 5 6 12 BAUD RATE 5 7 12 FLOW CONTROL 5 8 12 LOW POWER MODE 5 9 12 T3 TIMER 6 Application Design Considerations 13 6 1 13 LOCAL AND GLOBAL SETTINGS 6 2...

Page 4: ...cument est la propriété exclusive de WAVECOM Il ne peut être communiqué ou divulgué à des tiers sans son autorisation préalable 6 5 15 FLOW CONTROL AND BUFFER MANAGEMENT 6 6 16 OVERHEAD AND TIMING CONSIDERATIONS 6 7 17 OPTIMAL CHANNEL USAGE 7 Host Side MUX Driver Designs 17 8 References 18 Appendix A Basic MUX Procedures 19 27 010 MUX Feature Page 4 24 ...

Page 5: ...quipment DLC Data Link Connection virtual serial channel DTE Data Terminal Equipment FCS Frame Check Sequence HDLC High level Data Link Control ISO IEC 13239 1997 Host Application A TE side customer application MSC Modem Status Command MS Mobile Station i e GR GS64 Wireless CPU MO Mobile Originated MT Mobile Terminated MUX Multiplexer SABM Set Asynchronous Balanced Mode Serial Mode The Non MUX mod...

Page 6: ...lexing of data if the structure of the data has to be conveyed a convergence layer may be necessary The 3GPP 27 010 specification is intended to define a protocol that can be used to emulate a serial port Each virtual channel does best effort emulation of a serial link Each channel may have individual flow control procedures for buffer management purposes and Modem Status Command MSC s are used to...

Page 7: ... in the use case examples in section 4 3 2 Intended Audience This application note is intended for integrators who have experience writing serial communication programs and intend to develop and integrate a host side MUX driver according to the GSM 27 010 specification and GR GS64 AT command manual Before reading this document readers should have a basic understanding of the 27 010 standard itself...

Page 8: ...tion using AT CGDCONT AT CGACT AT E2IPO etc and one for AT commands Enable the SMS unsolicited responses using AT CNMI in the AT command channel and host application can receive SMS notification right away Scenario 2 Unsolicited responses while in online data mode Serial mode A host application can not receive unsolicited responses in on line data mode If the host application relies on certain sta...

Page 9: ...ch between online data mode and online command mode in order to use AT commands such as AT CSQ The host application has to explicitly suspend GPRS session in order to switch between modes MUX mode The host application uses two virtual channels one for data connection and one for AT commands The host application can send data without being interrupted on the data channel while it sends AT CSQ and o...

Page 10: ...rial links with good quality 5 2 Convergence Layer Type 1 GR GS64 only supports convergence layer type 1 Convergence layer type 1 is used to transfer over channels where there is no need to convey the control signals such as embedded V 24 signals along with the information The V 24 information instead will be carried by the MSCs on the MUX control channel Only UIH frames are used for data frames 5...

Page 11: ...r individual DLCs In MUX mode AT commands such as AT IFC AT D AT S and AT C control the behaviours of individual DLCs virtual signals rather than the physical UART control signals DLCIs Data Link Connection Identifiers and virtual modem signals RTS CTS DTR DSR DCD and RI modem signals are specified in the MSC frames and MSCs are sent on the MUX control channel Virtual modem signals are mapped to t...

Page 12: ...n the MUX control channel Aggregate flow control is achieved by hardware and the hardware handshake signals are used instead of FCon and FCoff defined in 27 010 spec to provide fast response Please see section 6 5 Flow control and Buffer Management for more information 5 8 Low Power Mode Autonomous standby mode stays effective in MUX mode if it was enabled by AT E2RS232 command in serial mode befo...

Page 13: ...the affect of the change For example if a change is made on one MUX channel any other active MUX channel would also experience the change One example is the AT CGDCONT setting ATZ AT V and AT W allow the user to restore view and store the current profile parameters in non volatile memory AT Y specifies which profile gets loaded on start up of GR GS64 wireless CPU In the MUX mode the last channel t...

Page 14: ...he GPRS session is ongoing which in turn makes the air link limitation an important design consideration in the MUX mode 6 4 Application Data Recovery As discussed in section 6 3 GPRS can be suspended due to the nature of mobile class B A host application needs to have an application level mechanism to handle the possibility of temporary data loss either through a reliable transport protocol such ...

Page 15: ... at a higher level MUX layer than the layer that hardware flow control operates As a result de asserting virtual RTS on the host application side will stop flow on the GR GS64 side slower than it will by hardware RTS signal By the time the virtual RTS signal reaches the upper layer of target side some data could have already transmitted over the serial link e g from GR GS64 UART IO buffer to Host ...

Page 16: ...elow As a result a host application needs to determine what it should use as the maximum frame size Although overhead of MUX frames does not translate to air interface overhead it could change timing of the user data flow and buffer space requirements on the host application side If the frame size gets smaller overhead becomes proportionally higher On the other hand the larger the frame size the m...

Page 17: ...The number of channels should be carefully considered up front for the host application design 7 Host Side MUX Driver Designs In a typical host application that uses MUX 27 010 is part of a port driver which includes a port emulation entity that supports serial communication APIs The communication APIs vary from operating system to operating system and from device to device 27 010 standard defines...

Page 18: ... 2 4 0 0 and above should be used with GR GS64 products Serial port monitoring tools are helpful when it comes to debugging or evaluating the host side MUX driver Here are two examples of commonly used tools Free Serial Port Monitor http www serial port monitor com index html Portmon http www microsoft com technet sysinternals utilities portmon mspx 8 References 1 3GPP TS 27 010 V3 4 0 2002 03 Ter...

Page 19: ...MUX If SABM is not received on DLC0 within the timer T3 The eighth parameter of CMUX command GR GS64 returns to AT command mode Î F9 03 3F 01 1C F9 F9 03 3F 01 1C F9 Closing Flag Opening Flag DLC 0 SABM Length 0 FCS Í F9 03 73 01 D7 F9 F9 03 73 01 D7 F9 Closing Flag Opening Flag DLC 0 UA Length 0 FCS 3 Establish DLC 1 Î F9 03 FF 15 83 11 01 00 01 0A 1F 00 03 01 FB F9 F9 03 FF 15 83 11 01 00 Parame...

Page 20: ...and K parameters are set to 0 Windows size K is not applicable in basic option Î F9 07 3F 01 DE F9 F9 07 3F 01 DE F9 Closing Flag Opening Flag DLC 1 SABM Length 0 FCS Í F9 07 73 01 15 F9 F9 07 73 01 15 F9 Closing Flag Opening Flag DLC 1 UA Length 0 FCS Establish DLC2 Î F9 03 FF 15 83 11 02 00 01 0A 1F 00 03 01 FB F9 F9 03 FF 15 83 11 02 00 Gx64 APPLICATION NOTE This document is the sole and exclus...

Page 21: ...ening Flag DLC 0 UIH 01 0A 1F 00 00 00 FB F9 N1 31 N1 0 N2 0 K 0 FCS Closing Flag Priority 1 T1 10 Lower 8 bit Higher 8 bits Î F9 0B 3F 01 59 F9 F9 0B 3F 01 59 F9 Closing Flag Opening Flag DLC 2 SABM Length 0 FCS Í F9 0B 73 01 92 F9 F9 0B 73 01 92 F9 Gx64 APPLICATION NOTE This document is the sole and exclusive property of WAVECOM Not to be distributed or divulged without prior written agreement C...

Page 22: ... 05 07 09 EE F9 F9 03 FF 09 E1 05 MSC Type Command Length 2 UIH Type Opening Flag Length 4 DLC 0 07 09 EE F9 Closing Flag V 24 signal FCS DLC 1 Gx64 APPLICATION NOTE This document is the sole and exclusive property of WAVECOM Not to be distributed or divulged without prior written agreement Ce document est la propriété exclusive de WAVECOM Il ne peut être communiqué ou divulgué à des tiers sans so...

Page 23: ...3 01 92 F9 Closing Flag Opening Flag DLC 2 UA Length 0 FCS F9 03 73 01 D7 F9 Closing Flag Opening Flag DLC 0 UA Length 0 FCS Gx64 APPLICATION NOTE This document is the sole and exclusive property of WAVECOM Not to be distributed or divulged without prior written agreement Ce document est la propriété exclusive de WAVECOM Il ne peut être communiqué ou divulgué à des tiers sans son autorisation préa...

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