Choosing between a standard and proprietary wireless protocol

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Introduction

There is a bewildering array of choice when it comes to considering between a standard or proprietary wireless technology design. Choosing which route to take needs careful consideration and an analysis of which solution will best meet your needs and requirements. This guide highlights the benefits and the limitations of using standard protocols and takes you through the main questions you should be asking when making a decision.

Wireless technology choices

The table below details some example wireless standards, their features and common applications:

Technology/ Standard Frequency band Range Features Common applications
6LoWPAN 2.4GHz and sub-GHz 10-100m Internet access, meshed network Monitor and control via internet, smart street lighting
ANT+ 2.4GHz <10m Low power Health, sports monitoring
Bluetooth (Classic, Low Energy) 2.4GHz 10m to 200m (Bluetooth 5) Ubiquity in smartphones, meshing possible Wireless audio, proximity sensing, health and sports monitoring, sensing
Cellular 2G, 3G, 4G (including NB-IoT, Cat M1) Cellular bands: 450MHz to 2600MHz <40km Almost national coverage, high data rates Mobile voice and data, IoT device data, SMS (text)
IEEE 802.15.4 2.4GHz 10-100m Carries multiple protocols (Zigbee, Thread, 6LowPAN, …) Local wireless networks
LoRaWAN 868MHz <40km Low-rate messaging over long distances IoT sensors
NFC 13.56MHz <0.3m Security Contactless payment, access
UWB 3.1 to 10.6 GHz <10m Low power, high speed data Video transfer, range measurement
WiFi 2.4 to 5GHz <100m High speed, ubiquity Local networks, internet access, broadband
WiMAX 2-11GHz and 10-66GHz <50km High speed, common in some countries Wireless alternative to cable and DSL broadband
Wireless HART 2.4GHz 10-100m Industrial HART protocol Industrial monitoring and control
Zigbee 2.4GHz 10-100m Mesh networks Home, industrial monitoring and control

Standard protocols and some limitations

Standard protocols are often a good choice when considering new wireless systems as they are proven and cost-effective, and often widely adopted. Increasing complexity in devices and communications means that designs can be reused (in modular form or as IP blocks). However, it’s important to bear in mind their limitations, outlined here.

The push to include lots of features increases complexity

Often the desire to include as many features as possible can make the standard very complex. It then becomes much more difficult for the wireless system to meet the full criteria of the standard in a truly interoperable way (Zigbee has had a long journey in trying to ensure this). The embedded software needed to implement the standard can also become very complex and large, which can cost and usage implications for the final product.

Niche applications may not be served well

Some user requirements are only partially catered for with standard protocols. For example, energy-harvesting systems require cut-down and specific protocols to fully cater for their requirements. EnOcean’s (www.enocean.com) protocol for energy-harvested power sources which have very energy efficient transmissions is one such example (this type of technology eventually made it into Zigbee 3.0).

Many wireless system designers choose to develop wireless systems based on proprietary protocols if standard protocol implementations are too expensive, either from a licensing point of view, or require too much processing power to meet the budget of the end user. These custom designs are ‘lighter’ than the standards, lower cost, and meet niche performance and applications by utilising the wide choice in ISM-band devices and modules available.

The 10 questions you need to ask

Whilst every situation will be different, here is a list of the 10 topics to address before choosing between a standard or proprietary protocol route:

  1. Network topology

How many members/nodes will participate in the wireless network and what is the interaction between them?

  1. Range

What is the required range between the transmitter and receiver? Is the distance fixed or will it vary?

  1. Data rate

What speed will the data need be transmitted at? Will it be low speed (e.g. infrequent messages), such as for monitoring and some control applications, or high speed, such as for video transfer? Lower messaging rates usually offer the best opportunity for long transmission range.

  1. Power

Is there a special need for low power consumption? If it is to be battery powered, consider battery size, life, recharging needs, replacement intervals and related costs. Is energy harvesting (e.g. solar power) a possibility?

  1. Common standards

Are there common standards that have to be met to interoperate with other part of the system?

  1. Software

What communications software protocols fit the application best? It’s important to find the best solution for the job and use well-tried standard solutions and open-source software.

  1. Regulations

What regulations need to be considered? Almost all wireless technologies require conformity to a standard. Some require licensing if using frequencies or if usage is outside of the license-exempt rules.

  1. Security

Do you need inbuilt security measures? Many wireless standards have security measures defined including encryption and authentication, and standard security methods can be used on top of proprietary communications solutions.

  1. Module-based or chip-based?

A further factor to consider is the benefit of choosing a module-based solution compared to a self-development based on a chipset. The benefits of selecting a module-based solution include a shorter time to market, ability to re-use its device certification (usually) and the device being a field-proven technology in terms of temperature, and antenna loads, for example. The disadvantages are possible increased unit cost and size, mass and shape limitations.

Conclusion

Technology based on standard wireless protocols will often present a cheaper and easier to implement option but won’t always offer the best solution for the design needs. Equally, a proprietary protocol solution is more likely to offer all the solutions required but is likely to cost more in terms of development and implementation. With increasing complexity, the trend is towards using standards-based solutions wherever possible, reducing development costs and unit costs.

Choosing either a standard or proprietary wireless technology comes down to some basic factors.

You should choose a standard protocol if:

  • Your wireless system application is a close match to the purpose of the wireless standard
  • Your development budget is low or system designers are not available

You should choose a proprietary protocol if:

  • There is a need for low cost hardware using a low footprint (small memory usage) protocol
  • If there is not a good fit between your wireless system application and the protocol or if a standard protocol has to be ‘shoehorned’ into the system design

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