Presentation on theme: "USLP Interface and Processing between Coding & Sync Sub-layer and Data Link Protocol Sub-layer."— Presentation transcript:
USLP Interface and Processing between Coding & Sync Sub-layer and Data Link Protocol Sub-layer
Receiving Side Functionality Channel Coding and Sync 1.Accept demodulated symbol stream from physical layer 2.Search received symbol stream for CSM 3.De-randomize then Decode > if decoder fails to achieve a valid code block Signal decode failure, drop bits- and go to 1 > If decoder passes validity- continue –pass decoded bytes to delimiter 4 4.Delimit frame > If ‘unaligned’ case is specified – Search for ‘FSM’ and use either managed length (TM/AOS) or frame length from frame header (TC/Prox/USLP) to delimit frame plus frame validation rules (TC) > If aligned case –transfer frame is delimited 5.Deliver delimited transfer frame to protocol sub-layer 6.Go to 1 Managed Parameters Transfer Frame length (value contained in USLP frame header) Alignment—(‘Aligned’ or ‘Unaligned’) FM (‘FM’ pattern & FM length) CSM (‘CSM’ pattern & CSM Length) Note: FSM = Frame Sync Marker (new term to replace ASM)
Sending Side Functionality Transfer Frame is created Channel Coding and Randomization 1.Request a slice from buffer 2.Accept data 3.Encode data and Randomize 4.Pre-pend CSM to Code block 5.Serially output to transmitter 6.Return to 1. above 1.Request a Transfer Frame (TF) 2.Accept received data and enter into input buffer (go to 1 until at least 1 slice is complete) 3.Extract the fixed sized “data slice” to encode 4.If a “complete slice” is available- > extract slice deliver to A 5.If only an incomplete “slice” is available > add Idle bytes to complete the slice deliver complete slice to A 6.If zero bytes are available an Idle Slice is delivered to Output A A Coding & Sync Input Buffer (Slicing) Request a Transfer Frame ChannelAccess.request (Frame,*) Rate Buffering Managed Parameters Transfer Frame Length (Managed or Signaled) TF Alignment—(‘Aligned’ or ‘Unaligned’) FSM (‘FM’ pattern & ASM length) CSM (‘CSM’ pattern & CSM Length) Idle Slice (OID Frame or Idle data) based upon TF Alignment FSM Attachment Service Pre-pend FM only when set to ‘Unaligned’ To Physical Layer Coding & Sync Boundary Rate Buffering Note: FSM = Frame Marker (new term to replace ASM)
PROs of “Sliced” USLP CONs of “Sliced” USLP 1.Uncoupling of frame from code block allows complete independence allowing codes to be chosen independently from framing. 2.Variable frame size allows frames to expand or contract to desired size for all links. Conforms to needs of VCM process. 3.Variable length frames on all links allows for an optional Insert Zone (IZ) or OCF upon demand (if chosen, IZ or OCF would not have to appear on every transfer frame). 1.Uncoupling means frame error rate varies with size and alignment of transfer frame(s) within code block. 2.Requires synchronization in bit and symbol domain (2 sync markers).