A Flexible PHY Description Approach with Channel Bands

1. Larry Taylor, DTC (UK) Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Channel Bands] Date Submitted: [8 January, 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: [Channel Bands provide a generic PHY description and a large channel numbering space] Purpose: [This presentation supports proposed Channel Bands draft text.] 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. A Flexible PHY Description Approach Channel Bands Larry Taylor, DTC (UK)

3. Larry Taylor, DTC (UK) The Problem • 15.4 systems communicate using the notion of a ‘channel’ • Channel ‘names’ consist of a Channel Page Number and a Channel Number which together uniquely define the frequency and PHY mode parameters • 15.4g has too many unique channels to use the existing 15.4 channel naming procedure

4. Larry Taylor, DTC (UK) The Tools Available • 15.4 has the 32-bit Channel Page structure allowing up to 31 pages to be defined in the 5 high order bits. Each page can identify up to 27 channel numbers, 1 per bit. Pages 0 to 6 are currently allocated • Existing Channel Page definitions mix PHY modes and frequency bands in the same page. The total number of channels in all PHY modes is small enough to be uniquely mapped to bit positions in the channel pages • 15.4 also has PHY PIB attributes, such as phyChannelsSupported, where a device’s capabilities for operation can be held and interrogated. Other PHY PIB attributes identify the current channel (and hence channel centre frequency and PHY parameters) • One additional tool was identified in the SFO meeting, which is parametric description of a frequency band. All 15.4g members accepted this idea of a ‘band agnostic’ representation

5. Larry Taylor, DTC (UK) The Solution • A new concept is needed, but any new concept should be derived from existing 15.4 concepts to keep architectural alignment as much as possible • A new simple & elegant concept, consistent with existing 15.4 concepts, is introduced in the following slides

6. Larry Taylor, DTC (UK) New 15.4g Concepts (1) • Existing 15.4 concepts identify the communications channel as a ‘channel number’ which links a frequency specification and a PHY mode • There is exactly one PHY mode and one centre frequency for each channel number • Since we have too many combinations of PHY mode and centre frequency to use unique channel numbers to identify them we introduce a concept of a group of channels that occupy a frequency band – a ‘channel band’ • To retain architectural consistency with 15.4 there needs to be a link between the ‘channel band’ and a PHY mode • However, each of the proposed PHYs in 4g may operate over the same frequency bands so the ‘channel band’ must link to all the possible PHY modes that might apply

7. New 15.4g Concepts (2) • We also need to have an equivalent ‘name’ to the ‘channel’ of existing 15.4 so that disparate systems can exchange information about operating capabilities using common terms. The ‘name space’ must be large enough to accommodate all the permitted combinations of frequency and PHY mode • The current channel is formed of the tuple Channel Page : Channel Number • Finally, we would like to permit vendor defined extensions to be easily added to an implementation so the structures must be extensible

8. Larry Taylor, DTC (UK) The Channel Band • A Channel Band is described by a Channel Band descriptor which includes • A frequency band with one or more named centre frequencies • A PHY mode i.e. a set of PHY parameters completely characterising the PHY operation • We need to add a ‘name’ which uniquely identifies the Channel Band (see slide 12) • To fully characterize the operating mode we need to identify a given centre frequency within the frequency band • The new channel is the tuple: Channel Page : Channel Band : Channel Number

9. Larry Taylor, DTC (UK) 15.4 Channel Numbering Hierarchy • Channel = Channel Page : Channel Number

10. Larry Taylor, DTC (UK) 15.4g Numbering Hierarchy • Add the channel band abstraction • Channel Band • A frequency band with one or more contiguous centre frequencies separated by a constant distance (frequency) • Add channel within channel band • Identifies the centre frequency • Is consistent with the band agnostic representation • New Channel Numbering Hierarchy • Channel = Channel Page : Channel Band : Channel Number NB. Kazu noted that channel scan uses a bit map of channels to scan

11. Larry Taylor, DTC (UK) 15.4g Channel Page Structure • Page 7 bit positions index into a table of standard frequency bands • Page 8 bit positions identify Channel Band Descriptors

12. Larry Taylor, DTC (UK) Channel Band Descriptor • Channel Band Name • Uniquely identifies a Channel Band • Channel Page Number + Index of Channel Bit Position • Type Identifies PHY Mode • 0 – PHY is described by Parametric PHY Descriptor • >0 PHY index into a standard defined table of PHY Modes • Frequency Band Descriptor • Band Edge includes any guard bands and is the lowest frequency of the first sub-channel • Band extent is defined by number of sub-channels and their separation • Sub-channels are contiguous • PHY Descriptor • PHY Type identifies {FSK, DSSS, OFDM etc.} • Subsequent fields are type dependent • Have a descriptor for FSK PHY modes

13. Larry Taylor, DTC (UK) 15.4g Channel Name • The centre frequency of any 15.4g communications channel is • the centre frequency of the current channel • in the current channel band • of the current channel page • Channel Band Name identifies • Channel Page Number • PHY Mode (index into standard table or PHY Descriptor) • Frequency band (index into standard table or Frequency Band Descriptor) • The unique 15.4g channel name is therefore • Current Channel Band Name + current channel number

14. Larry Taylor, DTC (UK) System Management • New PHY PIB Attributes • phyNumberModesSupported • Total number of Channel Band Descriptors in phyChannelBandsSupported • phyCurrentChannelBandName • Uniquely identifies a channel band descriptor in phyChannelBandsSupported • phyChannelBandsSupported • Array of Channel Band Descriptors • Defines all supported PHY Modes in all supported frequency bands • Modified PHY PIB Attributes • phyCurrentChannel • Uniquely identifies one centre frequency in the current channel band • Requires amended definition since range will be >27 for some SUB frequency bands • Note also that a MLME Channel Scan would need a channel bit map as large as the range of phyCurrentChannel

15. Larry Taylor, DTC (UK) Summary • Extends 15.4 concepts to satisfy 4g requirements • Many frequency bands and many PHY modes • One new concept based on the existing channel number concept • Channel Page 7 for Standard (15.4g) defined frequency bands • Up to 27 standard frequency bands • No limit to number of PHY modes supported • Channel Page 8 for Extended non-standard frequency bands and/or PHY modes • Up to 27 vendor defined frequency bands and/or PHY modes • Channel Band array holds Channel Band Descriptors • Channel Band Descriptor encoding defines frequency band and PHY mode parameters • Compliant device supports all channels in supported Channel Bands • Extended page allows non-standard channel maps • Channel Band Name provides unique identifier name space • Enhance definition of phyCurrentChannel PIB attribute • Allows future enhancements • Additional standard frequency bands • Additional PHY Types and modes

16. Questions Larry Taylor, DTC (UK)