This document discusses proposed revisions to ISO 18000-7 referred to as Mode 2. Key proposed changes include improvements to the physical layer to improve performance and reduce costs, improvements to the medium access control layer for better channel efficiency, and additions to allow for peer-to-peer communications and unsolicited packet transmissions. The revised standard would support features like decreased device size, external communication events, amorphous networks, and longer reading ranges.

1. Mode 2 Revision to ISO 18000-7
DASH7 Alliance
20 July 2010
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2. Motivations, and New Ideas
• Members of the DASH7 Alliance began, in February 2009,
coming up with must-have feature upgrades for ISO
18000-7. These revisions, it has been deemed, are Features Made Possible
absolutely required to advance the adoption of ISO 18000-7 • Decreased device size (SoC’s, smaller batteries)
into markets that are served by similar, proprietary
• External communication events (sensor alarms,
technologies concurrently developed by these DASH7 passive RF integration)
Alliance members.
• Amorphous networks (lots of unstructured
‣ Improvements to PHY in order to improve performance and decrease mobile readers, fixed and mobile tags)
cost in modern silicon implementations
‣ Improvements to MAC for greater channel efficiency (i.e. CSMA) • Eliminate frequent, redundant polling
‣ Improvements in protocol for lower power and higher performance. • Dense inventory management
‣ Ability to formally encapsulate subprotocols (i.e. sensor protocols) • Over-the-air standardized configuration,
‣ Peer-to-peer communications commission, and upload/download
‣ Unsolicited packet transmissions (i.e. not reader-talks-first) • Support for location services
‣ Multiple Channels
• Longer range, for sparse, typically outdoor
‣ Adjustable/Adaptive data rate networks
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3. Revised PHY
More options, but actually more uniform in design
• Designed for optimized synthesis into HW Mode 1 Mode 2
for better cost and interoperability
‣ Packet = Preamble, Sync Word, Data Channel Size 500 kHz 216 kHz
‣ Single Bit period across entire packet
Channels 1 8
‣ Uses filtered FSK (nominally GFSK)
Modulation FSK ± 50 kHz GFSK ± 50 kHz
• Designed to support different regulatory
environments, optimally. Encoding Options Manchester PN9, FEC
‣ Configuration of Output Power
Normal: 55.6 kHz
‣ Configuration of available channels (up to 8) Symbol Rate 55.6 kHz
Turbo: 200 kHz
‣ Out of channel power limitations
Min: 27.8 kbps
Data Rate 27.8 kbps
• Basic PN9 allows for better data rate than Max: 200 kbps
today’s Manchester, optional FEC allows for
greater range & signal strength. Packet Sync Pulse width Sync word
Nominal TX EIRP N/A 0 dBm
• Similar enough to existing ISO 18000-7 PHY
that devices could reasonably support both Peak stopband EIRP N/A -40 dBm
old and new modes.
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4. Device Settings
New
Beyond just “tag & reader” Gateway
• Designed to handle traditional, Old
tag-reader architecture and peer-to-peer Interrogator
networks alike.
Power Consumption
• Subcontroller and Endpoint are generally
intended for the same hardware platform
(low cost SoC).
• By switching between Endpoint and
Subcontroller regimes, a single device can New
quickly go from tag-like to reader-like Subcontroller
behavior.
• Each device setting has a standardized, Old
state-based device operation for greater Tag
interoperability & consistency. New
Endpoint
Capability
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5. Revised MAC
Still a wake-on MAC, but modernized for today’s digital RF
• Wake-on design: ideal for asynchronous Mode 1 Mode 2
communication in uncertain environments,
but better than before. Addressing Unicast, Broadcast
Unicast, Broadcast,
‣ Supports external events, like sensor alarms Multicast
‣ CSMA method allows reliable transmission of
Reader-Talks-First, CSMA,
packets and superior channel efficiency. It works Access Methods
Slotted Aloha Reserved Slots
in Reader-talks-first or non-RTF modes.
‣ Synchronizer Packet (Countdown Packet Train) is Beacon Support No Yes
a new tool that makes UHF wakeup much more
power-efficient (10x), more customizable, and Multi-hop No Yes
more interoperable than before.
Mesh routing No No
• Still mostly session-less, but with:
‣ Filtering of adjacent networks Session Network ID, Session ID,
Session Attributes
‣ Ad-hoc encoding options (crypto, FEC, etc) incrementer Session Encodings
‣ Data fragmentation is now in the protocol domain
Fixed length, non-data Variable Countdown
entirely (no Session incrementer) UHF Wake Event
wakeup tone Packet Train
• Multicast Addressing replaces cumbersome Anything attributable with
Table Commands. Other Wake Events None
a 15963-style ID
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6. Revised Data Elements
Emphasis on data interoperability and backwards compatibility
• UDB is now readable and writeable UDB Elements
‣ Searchable (accepts queries)
Addressing Data
‣ Writeable, to defined and undefined (i.e. user) elements Device Feature List
‣ root/admin/guest privilege model PHY Configuration
MAC Configuration
• UDB stores PHY, MAC, and Protocol device configuration Channel Scan Configurations
registers, common among all devices and interoperable. Supported Sub-Protocols List New
UDB Type List DASH7
• UDB stores and supports all legacy UDB Elements Data Block List
Location Data List
• UDB stores data elements for encapsulated features IPv6 Address & Config
‣ Sensors (ISO 21451-7 compliant) Sensor Data & Alarms
‣ Authentication & Security (ISO 29167 compliant) Authentication Keys
‣ Other future features, like IPv6 address support
Routing Code
• New RDB (raw data block), is backward compatible with old, User ID Old &
informal raw data block, but adds root/admin/guest privilege Hardware Fault Status New
model. UDB Ext. Services
DASH7
Application Extension
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