MobileMAN%20%20Hardware%20development%20for%20the%20MAC%20module:%20current%20state%20and%20outlook%20%20by%20Ralph%20Bernasconi,%20Ivan%20Defilippis,

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MobileMAN Hardware development for the MAC
module current state and outlook byRalph
Bernasconi, Ivan Defilippis, Silvia Giordano,
Alessandro Puiatti SUPSI Manno Cambridge, March
23 2004
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• Contents
• Introduction
• Steps done
• Where we are
• Next steps
• Data structure description
• Cross-layering questions

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• IntroductionProjects 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

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Steps Done (1/5)

• Analysis of the Market for the 802.11
  implementations
• Which kind of solutions were present
• Which solution best suited our needs
• Cost
• Reliability
• Flexibility
• Access to the software code
• Access to the firmware
• Easy development environment
• Secure and prompt technical support

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Steps Done (2/5)

• Analysis of the implementation starting point in
  relation with the market analysis
• Starting from scratch
• Implementation fo all the chain MAC - BB - RF
• Starting from a middle point
• Implementation of the MAC only
• Starting from an already implemented solution
• Change software and firmware for our pourpose

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Steps Done (3/5)

• Choosed solution
• Starting from a middle point
• BB and RF already developed by Elektrobit AG
• DT20 Modem
• Ourselv MAC implementation on Texass Instrument
  DSP
• TI C6713 board

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Steps Done (4/5)

• Analysis of 802.11 standard in deep
• Procedures and flowchart for the TX/RX farther
  implementation
• Implementations on a single board
• CRC on FPGA
• TX/RX between MAC and BB
• Channel Sensig machanism on MAC, (MAC RF)
• MAC TX mechanism on DSP
• MAC RX mechanism on DSP
• Standard Backoff mechanism
• Regular 802.11 frame generation
• Fragmented frame generation

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Steps Done (5/5)

• Duplicate above steps in a second board
• 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

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Where we are

• TX/RX of regular 802.11 frames OK
• Backoff mechanism implemented
• TX/RX of fragmented frame OK
• RTS/CTS/DATA/AK handshake not yet implemented

DT20 - Modems
Level-Switch interfaces
JTAG interface
TI C6713 boards
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Next Steps

• RTS/CTS/DATA/AK handshake
• Test of Backoff standard
• Implementation on a third board
• Communication tests with three cards
• Implementation of new Backoff algorithm
• Communication between board and PC through
  FireWire interface
• Implementation of Data structure

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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

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Data Structure description (2/4)
Memory Data Area
Descriptor yn1
MAC header x
MAC h. yn1
Frame body x
Frame body yn1
FCS x
FCS yn1
Frame body x1
Descriptor xn
MAC to PHY Queue
MAC (DSP)
Frame body xn
Frame body xn1
Descriptor yn-1
Descriptor yn
MAC h. yn-1
Frame body yn-1
FCS yn-1
Frame
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Data Structure description (3/4)
Memory Data Area
Frame body x
Frame body x1
Descriptor xn
MAC (DSP)
Begin
Frame body xn
Descriptor xn1
Descriptor y
MAC header y
Frame body xn1
Frame body y
Descriptor y1
Begin
FCS y
MAC h. y1
Descriptor y2
Frame body y1
FCS y1
Frame
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Data Structure description (4/4)
Management of queues with different levels of
priority
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Cross-Layering Questions

• How we think to implement the cross-layering
• A shared memory area in the host?
• A s.m.a made in two blocks one in the host and
  one in the MAC?
• Other?
• Who is the manager of the cross-layering data
  flow?
• In which way the layers access the cross-layer
  area?
• Which parameters we have to put in the
  cross-layer area?

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• Questions?
• Thanks for your attention!