Weightless-P Standard is Designed for High Performance, Low Power, 2-Way Communication for IoT

Weightless was unveiled over two years ago, as a new standards for IoT leveraging “white space” spectrum, previously used by analog TV broadcasts, for free M2M / IoT communication using low power (10 years battery life) and cost-efficient hardware ($2 hardware) offering a range of 5 to 10 km. Development kits and base stations were scheduled for Q2 2014, but there’s either been some delays or they are only available to Weightless members, as you need to register to get notified once hardware becomes available.

The Weightless SIG (Special Interest Group) has not stopped working on the standard as there are now three Weightless standards: Weightless-W (using White band spectrum), Weightless-N (sub-GHz spectrum), and and newly announced Weightless-P offering similar features as 3GPP carrier grade solutions, but at lower costs and lower power consumption.

The key features of Weightless-P are shown below:

Excellent capacity and scalability for IoT deployment
- FDMA+TDMA in 12.5kHz narrow band channels offer optimal capacity for uplink-dominated traffic from a very large number of devices with moderate payload sizes
- Operates over the whole range of license-exempt sub-GHz ISM/SRD bands for global deployment: 169/433/470/780/868/915/923MHz
- Flexible channel assignment for frequency re-use in large-scale deployments
- Adaptive data rate from 200bps to 100kbps to optimise radio resource usage depending on device link quality
- Transmit power control for both downlink and uplink to reduce interference and maximize network capacity
- Time-synchronised base stations for efficient radio resource scheduling and utilisation
Bidirectional
- Supports both network-originated and device-originated traffic
- Paging capability
- Low latency in both uplink and downlink
- Fast network acquisition
- Forward Error Correction (FEC)
- Automatic Retransmission Request (ARQ)
- Adaptive Channel Coding (ACC)
- Handover, Roaming, Cell re-selection
Long range
- Lower data rates with channel coding provide similar link budget to other LPWAN technologies
- 2km in urban environment
Industrial-grade reliability
- Fully acknowledged communications
- Auto-retransmission upon failure
- Frequency and time synchronisation
- Supports narrowband channels (12.5KHz) with frequency hopping for robustness to multi-path and narrowband interference
- Channel coding
- Supports licensed spectrum operation
Ultra-low energy consumption
- GMSK and offset-QPSK modulation for optimal power amplifier efficiency
- Interference-immune offset-QPSK modulation using Spread Spectrum for improved link quality in busy radio environments
- Transmit power up to 17dBm to allow operation from coin cell batteries
- Adaptive transmit power and data rate to maximize battery-life
- Power consumption in idle state when stationary below 100uW (vs 3mW for the best cellular technologies)
Secure and efficient networking
- Authentication to the network
- AES-128/256 encryption
- Radio resource management and scheduling across the overall network to ensure quality-of-service to all devices
- Support for over-the-air firmware upgrade and security key negotiation or replacement
- Fast network acquisition and frequency/time synchronization
Low cost and complexity
- Using standard GMSK and offset-QPSK modulation channels ensures broad availability of hardware and no dependency on a single vendor
- Compared to UNB, narrowband operation is less sensitive to frequency offset and drift, allowing the use of lower cost, lower power XOs or DCXOs instead of TCXOs
- Maximal transmit power of 17dBm allows for integrated power amplifier
Open standard
- Brings the reliability and performance of cellular technologies at a fraction of the cost by avoiding any legacy or backward-compatibility concerns
- Ensures interoperability between the manufacturers
- Provides for multi-vendor support to stimulate ongoing innovation and minimize end user costs
- Royalty free IP minimizes production costs

Hardware for the new Weightless-P standard will be available in Q1 2016.

You may wonder about the differences between Weightless-W/-N/-P and which one you should use for your IoT project. The Interest group published a table comparing the three standards.

	Weightless-N	Weightless-P	Weightless-W
Directionality	1-way	2-way	2-way
Feature set	Simple	Full	Extensive
Range	5km+	2km+	5km+
Battery life	10 years	3-8 years	3-5 years
Terminal cost	Very low	Low	Low-medium
Network cost	Very low	Medium	Medium

So if one way communication is suitable, go with Weightless-N, if the “white-space” spectrum is available in your country go with Weightless-W, and otherwise you may want to select Weightless-P for high performance 2-way communications.

You can find some information on all three royalty-free standards on Weightless technical information page. But if you want access to the full specifications for your project(s), you’ll need to become a Weightless members with membership starting at 900 GBP (~$1400) per year for “associate” members.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.