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MobileMAN Hardware development for the MAC module current state and outlook IAB meeting By Ralph Bernasconi, Ivan Defilippis, Silvia Giordano, Alessandro Puiatti SUPSI Manno Helsinki, June 7-8 2004. Contents Introduction Completed work Current work Next steps
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MobileMANHardware development for the MAC module current state and outlookIAB meeting By Ralph Bernasconi, Ivan Defilippis, Silvia Giordano, Alessandro Puiatti SUPSI Manno Helsinki, June 7-8 2004 MobileMAN meeting, Helsinki
Contents • Introduction • Completed work • Current work • Next steps • Data structure description • Questions? MobileMAN meeting, Helsinki
IntroductionProject’s SUPSI-DIE goals (reminder) • Provide flexible development- and test-bed for enhanced WLAN protocol (CNR) • Bursty responsive MAC • Better contention scheme (backoff); avoid collisions even for dense and active networks • Ensure compatibility with 802.11x • Provide few samples to partners • Provide inputs for new standard MobileMAN meeting, Helsinki
Completed work (1/8) • Analysis of the Market for the 802.11 implementations • Available solutions? • Which solution best suits our needs? Criteria are: • Cost • Reliability • Flexibility • Access to the software code • Access to the firmware • Easy development environment • Secure and prompt technical support MobileMAN meeting, Helsinki
Completed work (2/8) • Alternatives for development: • Start from scratch: • Implementation of a complete chain: MAC - BB - RF • Start “in the middle”: • Implementation of the MAC only • Start from an already implemented solution: • Change software and firmware for our purpose MobileMAN meeting, Helsinki
Completed work (3/8) • Selected solution • Start “in the middle” • BB and RF already developed by Elektrobit AG: • DT20 Modem (Intersil Prism-I chipset) • Implement MAC on a DSP microcontroller • TI C6713 board (Texas Instruments) MobileMAN meeting, Helsinki
DT20 - Modems Level-Switch interfaces JTAG interface TI C6713 boards Completed work (4/8) • Development system MobileMAN meeting, Helsinki
Completed work (5/8) MobileMAN meeting, Helsinki
Completed work (6/8) • Deep analysis of the 802.11 standard • Procedures and flowchart for the Tx/Rx further implementation • Implementation on the DSP board • CRC on FPGA • Tx/Rx between MAC and BB • Channel Sensing mechanism on MAC (MAC – RF) • MAC Tx mechanism • MAC Rx mechanism MobileMAN meeting, Helsinki
Completed work (7/8) • Implementations on the DSP board (cont.) • Standard backoff mechanism • Regular 802.11 frame generation • Fragmented frame generation • RTS/CTS/DATA/AK handshake • MAC Address recognition • Channel contention MobileMAN meeting, Helsinki
Completed work (8/8) • Tests done (2 systems/boards) • Stress tests in Tx between boards connected by cable • Stress tests in Rx between boards connected by cable • Stress tests in Tx/Rx between boards connected by cable • Stress tests in Tx/Rx between boards in wireless mode • Standard backoff tested successfully • Fragmented Tx/Rx tested successfully • RTS/CTS/DATA/AK handshake tested successfully MobileMAN meeting, Helsinki
Current work • Assembly of the 3rd system/board • Definition of the host interface mechanism(via IEEE-1394/FireWire) • Definition of the standard packets data-structure • Definition of data-structure extensions for cross-layering implementation MobileMAN meeting, Helsinki
Next steps • Implementation on the DSP • NAV (Network Allocation Vector) • Test of a 3 nodes network (with above functionality) • Implementation and test of the host interface mechanism • Implementation and test of the standard packets data-structure • Implementation and test of data-structure extensions for cross-layering • Implementation and test of the modified (CNR-Pisa) backoff mechanism MobileMAN meeting, Helsinki
Data Structure description (1/4) • Memory slotted in parameterized slot length (default frame max length) • Descriptor mechanism for handling data • Different queues for managing data transfer: • From MAC to PHY and from PHY to MAC • From MAC to Host and from Host to MAC • Implementation of priority mechanisms for each queue • Control flags in descriptor in which: • DATA = Frame • DATA = parameters for/from cross-layering MobileMAN meeting, Helsinki
Host to MAC Queue Begin End MPQ Descriptor x Host to MAC Queue Begin Descriptor x+1 Descriptor x+n+1 End HMQ End HMQ MAC h. y+n Frame body y+n End MPQ FCS y+n Data Structure description (2/4) Memory Data Area Descriptor y+n+1 MAC header x MAC h. y+n+1 Frame body x Frame body y+n+1 FCS x FCS y+n+1 Frame body x+1 Descriptor x+n MAC to PHY Queue MAC (DSP) Frame body x+n Frame body x+n+1 Descriptor y+n-1 Descriptor y+n MAC h. y+n-1 Frame body y+n-1 FCS y+n-1 Frame MobileMAN meeting, Helsinki
MAC to Host Queue Begin Descriptor x Descriptor x+1 PHY to MAC Queue PHY to MAC Queue End MHQ End MHQ MAC h. y+2 Frame body y+2 End PMQ FCS y+2 Data Structure description (3/4) Memory Data Area Frame body x Frame body x+1 Descriptor x+n MAC (DSP) Begin Frame body x+n Descriptor x+n+1 Descriptor y MAC header y Begin Frame body x+n+1 Frame body y Descriptor y+1 FCS y MAC h. y+1 Descriptor y+2 Frame body y+1 FCS y+1 Frame MobileMAN meeting, Helsinki
Descriptor k Pn Descriptor 2 P0 Descriptor h Pn-1 Descriptor 2 Pn-1 Descriptor 4 Pn Descriptor 3 P0 Descriptor 2 Pn Descriptor 1 Pn Descriptor g P0 Descriptor 3 Pn End Q-Pn Descriptor 1 Pn-1 End Q-Pn-1 Descriptor P0 End Q End Q-P0 Data Structure description (4/4) Management of queues with different levels of priority MobileMAN meeting, Helsinki
Questions? • Thanks for your attention! MobileMAN meeting, Helsinki