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Channel Bands Update - Separation of Standard Channel Page and Generic PHY Channel Page

This submission provides an update on the Channel Bands draft text, separating the standard channel page description from the generic PHY description and defining a channel numbering scheme for standard 15.4g operation.

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Channel Bands Update - Separation of Standard Channel Page and Generic PHY Channel Page

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Channel Bands Update] Date Submitted: [10 February, 2010] Source: [Larry Taylor] Company [DTC (UK)] Address [UK] Voice:[], FAX: [], E-Mail:[larry.taylor@discretetime.com] Re: [Draft 15.4g draft FSK text] Abstract: [Update on Channel Bands – corrects a duplicate PHY PIB attribute name in 15-10-0007-02] Purpose: [This presentation supports updated Channel Bands draft text in 802.15-10-0008-1] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

  2. Separate Standard Channel Page & Generic PHY Channel Page structures Channel BandsUpdate

  3. Focus of the Update • The general form of the Channel Band Descriptor provides a very powerful generic PHY description mechanism • However, the Standard PHYs don’t need the general form of the descriptor • This update separates the standard channel page description (Channel Page 7) from the Generic PHY description (Channel Page 8) and defines a channel numbering scheme for standard 15.4g operation

  4. Part I – Standard Operation Channel Numbering

  5. Reminder – The Problem • 15.4g defines • A large number of frequency bands (~20) • A large number of PHY Modes (~50) • Different data rates, channel separation, modulation • Any PHY Mode may operate over a frequency band • Not all combinations are defined, but in general all are possible • This results in a very large number of distinct channels – far more than can be represented using the 32-bit Channel Page/Channel Number structure

  6. Existing Constraints • Many MAC Management primitives and MAC Commands use Channel Page and Channel Number parameters • To maintain consistency with existing 15.4 specifications the extended channel numbering model must retain Channel Page and Channel Number structure • In addition, the MLME-SCAN primitive has an explicit ScanChannels parameter defined as a 27-bit field • Needs re-definition for 15.4g • Field size is PHY Mode & frequency band dependent

  7. 15.4g Channel Page 7 Structure • Define Channel Page 7 for 15.4g • Bit positions index into the table of standard frequency bands • A device sets the corresponding bit to 1 for each standard frequency band supported • It is a convenient way of avoiding defining a PHY PIB attribute phyFrequencyBandsSupported

  8. Each bit position in Page 7 corresponds to an index in the Standard Frequency Band Table Bit 20..27 are unused and reserved for future use Page 7 Bit Index

  9. Current Frequency Band • Add a PHY PIB attribute phyCurrentFrequencyBand • Value is an index into the standard frequency band table • Must correspond to a bit set to 1 in Channel Page 7 bits 0..26 • Identifies which of the supported standard frequency bands is currently being used

  10. PHY Mode • Add a PHY PIB attribute phyPHYModesSupported • A bit mask of supported PHY Modes (bit set to 1) with each bit corresponding to an index into the table of standard PHY Modes • Size is determined by the number of standard PHY Modes • Add PHY PIB attribute phyCurrentPHYMode • Its value is an index into the table of standard PHY Modes and must correspond to a bit set to 1 in phyPHYModesSupported

  11. Channels Supported • The current 15.4 channel bit mask in bits 0..26 of the Channel Page indicate which channels are supported • Allows a subset of possible channels to be supported • Also used for channel scanning • Add a PHY PIB attribute phyCurrentChannelsSupported to hold the channel bit mask for the current frequency band • Size is frequency band and PHY Mode dependent

  12. Number of Channels • Add a PHY PIB attribute phyNumberChannels • Identifies the number of channels for phyCurrentPHYMode in phyCurrentFrequencyBand • Also identifies the number of significant bits in phyChannelsSupported

  13. Current Channel • The current channel is therefore determined by: • phyCurrentChannel • A number in the range 0..phyNumberChannels-1 • Corresponding bit position in phyCurrentChannelsSupported must be set to 1 • phyCurrentFrequencyBand • A bit position in Page 7 set to 1 • Indexes table of standard frequency bands • phyCurrentPHYMode • An index into the table of standard PHY Modes

  14. Standard Canonical Name • To support negotiation of mode of operation by higher layers • Index values of standard frequency bands and PHY Modes • Channel number is qualified by • standard frequency band phyCurrentFrequencyBand • PHY Mode phyCurrentPHYMode • Channels supported phyChannelsSupported

  15. PHY PIB Attributes • New PHY PIB Attributes • phyCurrentFrequencyBand • Value is an index into the table of standard frequency bands and must correspond to a bit position in Channel Page 7 set to 1 • phyPHYModesSupported • Bit mask of PHY Modes supported. Each bit corresponds to an index into the standard table of PHY Modes • phyCurrentPHYMode • Value is an index into the table of standard PHY Modes and must correspond to a bit set to 1 in phyPHYModesSupported • phyNumberChannels • Value is the number of channels in phyCurrentFrequencyBand for phyCurrentPHYMode • phyCurrentChannelsSupported • Channel bit mask of size phyNumberChannels identifying which channels may be used in the current freqency band • Modified PHY PIB Attributes • phyCurrentChannel • Requires amended definition since range will be >27 for some SUN frequency bands and is frequency band and PHY Mode dependent • phyCurrentChannel must correspond to a bit position in phyCurrentChannelsSupported set to 1

  16. Part II – Generic PHY The Channel Band Descriptor

  17. The Problem • To allow 15.4g compliant systems to declare vendor specific modes of operation in a standard way • Permit exchange and negotiation of operating parameters (frequency band and PHY Mode) • Provide efficient short canonical name suitable for use in commands

  18. 15.4g Channel Page 8 Structure • Define Channel Page 8 for 15.4g • Each bit 0..26 (set to 1) identifies a Generic PHY descriptor

  19. Generic PHY Descriptor • Generic PHY Descriptors are only in Channel Page 8 • Page 8 + ID forms a canonical name • Frequency descriptor part based on band agnostic representation • Parametric PHY part is PHY Type dependent • Parameters for FSK PHY are suggested

  20. PHY PIB Attributes • Add PHY PIB attribute phyNumberGenericPHYDescriptors • Add PHY PIB attribute phyGenericPHYDescriptors • Array of phyNumberGenericPHYDescriptors elements each one containing a Generic PHY Descriptor • Elements are uniquely identified by ID in the local system • Add PHY PIB attribute phyCurrentGenericPHYDescriptor • Value is the ID of a Generic PHY Descriptor and must correspond to a bit set to 1 in bits 0..26 of Channel Page 8

  21. Part III – Mode Switch Support

  22. Mode Switch PPDU • Flag in the PHY Header identifies a frame PPDU variant for Mode Switching • The Frame needs a parameter to identify the operating mode of the subsequent PPDU • The canonical name serves as this parameter

  23. Canonical Name (1) • The canonical name is made up of two parts • Frequency Band part • PHY Mode part • Channel Page 7 • Frequency Band part is the bit index in channel page 7 and is the value of phyCurrentFrequencyBand • PHY Mode is the value of phyCurrentPHYMode and is an index into the PHY Mode table • Channel Page 8 • phyCurrrentGenericPHYDescriptor holds the ID of a generic PHY descriptor • Both Frequency Band & PHY Mode are identified in the generic PHY descriptor

  24. Canonical Name (2) • The canonical name is therefore • Channel Page (7) : Frequency Band Index : PHY Mode index • Channel Page (8) : Generic PHY Descriptor ID • An encoding in 16 bits (or less) is possible • The Mode Switch also needs a target Channel Number field

  25. Questions

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