Non TCP/IP Wireless Protocols

Protocols designed for specific low-power, short-range use cases. TCP/IP carries too high a footprint for many embedded and sensor applications. Protocol selection is application-driven: each trades data rate, range, and power against complexity.

Legacy non-IP protocols: SNA, DECNet, Novell Netware, NetBEUI, WAP.
Current relevant protocols: Bluetooth, ZigBee, NFC, Fiber Channel.

Bluetooth

Short-range wireless protocol for cable replacement, multiparty data exchange, and personal trusted device connectivity. Developed by Ericsson; managed by the Bluetooth Special Interest Group. Standardized as IEEE 802.15.1. Originally a wireless alternative to RS-232 data cables.

• Band: 2.4–2.48 GHz (ISM).
• Range: ~10 m.
• Bandwidth: 2.1 Mbps shared (v2.0).
• Version 4.0 variants: Classic Bluetooth, Bluetooth High Speed (Wi-Fi-based), Bluetooth Low Energy (BLE).

Protocol Stack

Divided into a Transport Protocol group and a Middleware Protocol group.

Transport layers, bottom to top:

• Bluetooth Radio: radio signal modulation and transmission.
• Baseband: frequency-hopping and time-division multiplexing between master and slaves.
• Link Manager Protocol (LMP): logical channel establishment, authentication, power management.
• Host Controller Interface (HCI): software interface to baseband and link manager; exposes hardware status and registers.
• L2CAP (Logical Link Control and Adaptation Protocol): multiplexes multiple logical connections; provides segmentation and reassembly of on-air packets. Primary layer from the application developer’s perspective.

Middleware layers:

• RFCOMM: cable replacement protocol; emulates EIA-232 (RS-232) serial interface.
• SDP (Service Discovery Protocol): discovers services offered by other Bluetooth devices.
• TCS-BIN (Telephony Control Specification, Binary): establishes speech and data calls between master and slave.
• OBEX (Object Exchange Protocol): exchanges structured data objects such as calendars and vCards.
• Audio: supports audio communication directly on top of Baseband.

Network Topology

Piconet

Basic Bluetooth network unit. All communication goes through the master. No direct slave-to-slave communication.

• Up to 7 active slaves.
• Up to 255 parked (inactive) slaves.

Scatternet

Formed by connecting 2+ piconets. A device can act as slave in one piconet and master in another simultaneously.

Profiles

A profile is a set of application-layer protocols defining behaviors for a specific use case. Profiles reside on top of the Bluetooth core specification.

Examples:

• HFP: Hands-Free Profile.
• BPP: Basic Printing Profile.
• AVRCP: Audio/Video Remote Control Profile.
• FTP: File Transfer Profile.
• HID: Human Interface Device Profile.
• PAN: Personal Area Networking Profile.
• GOEP: Generic Object Exchange Profile (uses OBEX).

Near Field Communication

Also known as NFC. Short-range wireless communication based on magnetic field induction between readers and tags in RFID systems. Initiated in 2004 by Nokia, Philips, and Sony.

• Frequency: 13.56 MHz.
• Range: 10 cm or less.
• Data rate: 106–424 Kbps.

Advantages: low cost, low energy, no search/pair procedure, minimal configuration, better security.
Limitations: low range, low data rate.

Used in: mobile payments, public transportation, mobile identification, mobile marketing, social networking, check-in.

Modes of Operation

• Active Mode: both devices generate electromagnetic fields and exchange data.
• Passive Mode: one active device generates the field; the passive device uses that field to exchange data.

Application interaction patterns: Touch & Go, Touch & Confirm, Touch & Connect.

Protocol Stack

Three operational modes, each with distinct stack components:

• Card Emulation Mode: smart card capability for mobile devices.
• Peer-to-Peer Mode: LLCP (Logical Link Control Protocol) with NFC Forum Protocol Bindings (IP, OBEX).
• Reader/Writer Mode: RTD (Record Type Definition) with NDEF (NFC Data Exchange Format) and Tag Types 1–4.

Underlying RF layer: ISO 18092 with ISO 14443 Type A/B and FeliCa.

ZigBee

Low-power, low-data-rate wireless protocol by the ZigBee Alliance. Targets sensor networks and IoT applications.

• Power consumption: months to years of battery life.
• Max data rate: 250 Kbps.
• Low circuit complexity, low cost.

Protocol Stack

Built on IEEE 802.15.4 (physical and MAC layers for low-rate WPAN).

ZigBee adds three layers above 802.15.4:

• NWK (Network Layer): routing, route discovery, route maintenance.
• APS (Application Support Sub-Layer): service binding and message routing between application objects.
• APL (Application Layer): Application Objects and ZigBee Device Objects.

Device Types

Defined by IEEE 802.15.4:

• FFD (Full Functional Device): operates as PAN coordinator, coordinator, or simple device; communicates with FFD or RFD.
• RFD (Reduced Functional Device): communicates only with a specific FFD; suited for low-volume, simple applications.

Topologies

Star:

• Central PAN coordinator; all devices connect directly to it.
• Pros: easy synchronization, low latency.
• Cons: small scale only.

Mesh / Peer-to-Peer:

• Devices communicate directly with any in-range device.
• Pros: robust multi-hop communication, multi-path routing, flexible, lower latency.
• Cons: costly route discovery, requires routing table storage.

Cluster Tree:

• Hierarchical arrangement of coordinators and devices.
• Pros: low routing cost, multi-hop, scalable.
• Cons: costly route reconstruction, potentially high latency, root node is a single point of failure.

Traffic Modes

Beacon Mode:

• Coordinator periodically broadcasts a beacon.
• Both coordinator and end device can sleep between beacons.
• Lowest energy consumption; requires precise timing.
• Beacon period: milliseconds to minutes.

Non-Beacon Mode:

• Coordinator/routers must remain awake continuously.
• Supports heterogeneous networks with asymmetric power requirements.

Route Discovery

Broadcast-based protocol:

1. Source broadcasts RREQ (Routing Request) packet.
2. Intermediate nodes generate routing table entries back to source.
3. Endpoint router responds with RREP (Routing Response) packet.
4. Source generates routing table entry to destination.

Route maintenance tracks failed deliveries to neighbors and initiates route repair at a threshold. On total connectivity loss: orphaning procedure followed by re-association.

Comparative Summary