ITU - Telecommunication Standardization Sector
`
`Temporary Document _09XC-119
`
`STUDY GROUP15
`
`Original: English
`
`Xi’an China — 27 — 31 July 2009
`
`Question: 4/15
`
`SOURCE’: Intellon Corporation
`
`TITLE:
`
`G.hn: Extended PHY frame header
`
`
`ABSTRACT
`
`This contribution proposes to add an option for supporting extended PHY frame headers that contain 2 x PHY»
`information bits in order to allow for expansion of the ACKIfield and to allow additional header bits for future
`enhancements to G.9960.
`
`
`| Introduction | First Heading | Second Heading | Summary
`
`1. Introduction
`
`The G.9960 draft in §7.1.2.1 alludes to PHY frame headers that contain more than one symbol (although the reference
`does not makeit clear if this is for PHY frame header symbol repetition or to support additional PHY frame header
`information bits), and support for extended PHY frame headers with additional information bits that are encoded with
`double the symbols used for the non-extended PHY frame header has been discussed in the G.hn group. However,
`currently, the current text (G.9960 draft, G.9960 AmendmentI, or G.hn draft) does not describe support for more than
`PHYxinformation bits in the PHY frame header.
`
`This contribution proposes to add an option for supporting an extended PHY frame header with 2 x PHYy information
`bits in order to allow for expansion of the ACKI field and to allow additional header bits for future enhancements to
`G.9960. A larger ACKIfield allows more frames to be acknowledged, and is especially useful for bi-directional
`transmissions, which is proposed in separate contribution.
`
`Proposed is to define two one-bit fields which are assignedto bits in the PHY frame headerthat are currently reserved.
`The extended header indication (EHI) is set to indicate that the PHY header contains 2 x PHYy informationbits,
`allowing receivers to determine how to decode the PHY header.
`
`The immediate response frame extended header indication (IREHI) tells receivers if they should respond with a header
`than contains PHYy or 2 x PHYy information bits when transmitting immediate response frames. This allows
`receivers to know if sufficient time has been allocated for a immediate response frame and for nodes tracking durations
`to know the duration of a frame transmission sequence. If at some point the definition of the duration field is modified
`so that it includes immediate response frames (ACK frame), then it may be possible to eliminate the IREHIbit.
`
`This contribution proposes two HCSfields to independently protect the content of each set of PHYy information bits in
`the PHY header. Two independent HCSfields results more robust protection of the header contents. It also eliminates
`ambiguity for receivers when determining how to decode the PHY frame header. Ifa single HCS field were to be
`defined that protected 2 x PHY} information bits then the IREHI bit would needto be interpreted and acted on before
`the bit is verified with the HCS.
`
`‘Contacts:
`
`Sid Schrum,Intellon Corporation
`
`sit. achrum@inicllon cam
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`Page 1 of 4
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`DELL-1019
`10,079,707
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`DELL-1019
`10,079,707
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`Page 1 of 4
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`

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`2. Proposed Text Updates
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`<<Start Text — G.9960 Amendment I>>
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`7.1.2.3
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`PHY-frameheader
`
`
` The PHYframe header PHY,
`
`de x and is composed of a common part and a variable part.
`The common‘part containsfields that are commonforall PH'Y-frame types. The variable part containsfields according
`to the PHY-frame type. PHY-frame type is indicated by the FT field. The PAD fieldsfit the length of the header of
`different PHY frame-types to the standard values of PHY:bits. The content ofthe header is protected by the 16-bit
`ter).
`header check sequences (HCS,
`and
`i
`
`The fields of the PHY-frame header are defined in Table 7-1
`
`Table 7-1/G.9960 — PHY-frame headerfields
`
`
`
`Field Field Size|Description
`[Bits]
`jFr[OOFrametypeiCommonpart
`|DOD
`|SID
`|DID
`
`
`
`
`o DID is a multicast destination
`nt
`firstpayloadsymbolaftertheheaderisa
`
`Post header indication identifies whether the
`
`
`
`
`
`Header check sequence
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`Page 2 of 4
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`Page 2 of 4
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`

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`7 A231.8 Header check sequences
`
`
`ages Intended for PHY-frame headerverification. The HCS is a 16-bit cyclic redundancy
`3
`The HCS apd 85S
`check (CRC) and shall be computed overall the fields of the rst
`‘
`¢PHY-frame header in
`
`the order they are¢ transmitted, starting with the MSB ofthe frame type (FT) fieldandending with theLSB ofthe last
`field x5
`ths
`a
`bits of the PHY Frame. %
`
`
`
` The HCS shall be computed using the following generator polynomial of degree 16:
`
`G(x) = EP a S41,
`The value ofthe HCS a
`HS
`shall be the remainderafter the contents (treated as a polynomial where the first
`
`input
`bbit is associated with tthe highestdegree, XMMwhere PHY} is the 3
`4
`f
`Ffheader3
`sig
`
`A, and the last input bit is associated with x°) ofthe calculation fields is
` multipliedbyxx!*andthen divided by Gfx).
`
`3fields shall be transmitted starting with the coefficient of the highest order term (MSB).
`
`
`The HCS a
`
`7.1.2.3.2.2 ACK PHY-frametype specificfields (working text)
`Table 7-11.1 lists the ACK PHY frametype specific fields.
`
`Table 7-11.1/G.hn — ACK PHY FrameTypeSpecific Fields
`
`
`
`RBA TR
`x
`Ratti.
`
`<<End Text - G.9960 Amendment [>>
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`Page 3 of 4
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`Page 3 of 4
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`3. Summary:
`
`
`| Introduction | First Heading | Second Heading | Summary
`
`This contribution is intended to be discussed at the G.hn meeting to be held in Xi’an China — 27 — 31 July 2009.
`
`This contribution proposes changes to workingtext.
`
`Specifically proposed are the following new agreements:
`
`
`
`§.0.1.2.1.0.2
`15
`
`New
`
`should the PHY frame header numberof information bits be
`optionally expandable to 2 x PHYHbits as described in
`contribution 09XC-119?
`
`09XC-119
`
`New
`
`5.0.1.2.1.0.2
`1.6
`
`should the text proposed in §2 of 09XC-119 that adds fields and
`description for supporting extended PHY-frame headers be
`incorporated as a revision of working text for §7.1.2.3 “PHY-
`frame header” and the sub-clauses for §7.1.2.3 in G.9960
`
`Amendment 1?
`
`09XC-119
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`Page 4 of 4
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`Page 4 of 4
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