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Low Power Wide Area Networks: A Survey of Enabling Technologies, Applications and Interoperability Needs

Qahhar Muhammad Qadir, Tarik A. Rashid, Nawzad K. Al-Salihi, Birzo Ismael, Alexander A. Kist, Zhongwei Zhang

arXiv:2008.08639v1cs.NI

TL;DR

IoT applications need networks combining wide coverage, low power, low data rates, and affordable devices, while diverse LPWA technologies create integration and selection challenges. This survey compares LPWA technologies and related wireless systems, analyzes markets and research, recommends solutions for use-cases, and identifies operational challenges. It concludes that integration among LPWA technologies and use-case-specific recommendations are central needs, while real-time requirements distinguish suitable technologies.

  • Problem

    IoT applications require wide coverage, low power, low data rates, and affordable devices, but LPWA technologies remain diverse and face integration, operational, and security challenges.

  • Method

    The paper surveys and compares LPWA technologies, analyzes markets and research efforts, proposes integration needs, and evaluates technologies against IoT use-case requirements.

  • Results

    For two-way control applications requiring 28.8 kbps, LoRaWAN, RPMA, and NB-IoT meet the data-rate requirement, while only RPMA and NB-IoT meet minimum IP-video-surveillance rates.

  • Takeaways & Limitations

    LPWA selection should be matched to application requirements, and integrating diverse LPWA technologies can support connectivity across underlying radio technologies.

Abstract

from arXiv · show

Low power wide area (LPWA) technologies are strongly recommended as the underlying networks for Internet of things (IoT) applications. They offer attractive features, including wide-range coverage, long battery life and low data rates. This paper reviews the current trends in this technology, with an emphasis on the services it provides and the challenges it faces. The industrial paradigms for LPWA implementation are presented. Compared with other work in the field, this survey focuses on the need for integration among different LPWA technologies and recommends the appropriate LPWA solutions for a wide range of IoT application and service use-cases. Opportunities created by these technologies in the market are also analyzed. The latest research efforts to investigate and improve the operation of LPWA networks are also compared and classified to enable researchers to quickly get up to speed on the current status of this technology. Finally, challenges facing LPWA are identified and directions for future research are recommended.

I. INTRODUCTION

LPWA networks target IoT applications needing low data rates, low power, affordable devices, and wide-area communication. This survey compares wireless technologies, reviews LPWA trends and markets, argues for integration, recommends technologies for use-cases, and identifies research challenges.

  • I. INTRODUCTION: LPWA targets IoT applications requiring low data rates, low power consumption, affordable devices, and communication across wide geographical areas.These applications span sectors including transportation, healthcare, agriculture, and industry.
  • I. INTRODUCTION: Legacy short-range and cellular networks create limitations through restricted coverage, substantial device energy use, or insufficient suitability for low-power, low-cost IoT devices.Non-cellular technologies cover only a few hundred meters, while traditional cellular technologies require considerable energy.
  • I. INTRODUCTION: The paper surveys current LPWA trends, dominant technologies, IoT support, and associated challenges to consolidate the field for researchers.The authors justify another survey because LPWA remains a relatively new research area.
  • I. INTRODUCTION: Unlike prior surveys with narrower technology or standardization scopes, this paper emphasizes integration among LPWA solutions and recommends technologies for diverse IoT use-cases.It also compares and categorizes recent LPWA research and analyzes market opportunities.
  • I. INTRODUCTION: The survey compares short- and long-range M2M technologies across power, energy, licensing, SINR, data rate, reliability, and end-device active time.It presents these trade-offs in the context of IoT requirements.

A. SHORT-RANGE M2M WIRELESS TECHNOLOGIES

Short-range M2M technologies such as ZigBee are designed for low-power local connectivity but remain constrained in coverage, capacity, and suitability for large-scale IoT deployments.

  • A. SHORT-RANGE M2M WIRELESS TECHNOLOGIES: Short-range technologies are compared through their technical features, application use-cases, ranges, data rates, energy efficiency, and terminal and connection costs.The supplied figures and table identify these comparison dimensions without reporting their unseen values.
  • A. SHORT-RANGE M2M WIRELESS TECHNOLOGIES: ZigBee connects low-power wireless personal devices in small areas, offering up to 250 kbps and supporting up to 255 devices within 100 m.It has been used in building automation, industrial monitoring, fitness, healthcare, agriculture, and environmental monitoring.
  • A. SHORT-RANGE M2M WIRELESS TECHNOLOGIES: IEEE 802.15.4-based ZigBee is unsuitable for IoT applications requiring large-area coverage and communication among many devices.Its stated coverage and connectivity limits are 100 m and 255 devices.

2) Bluetooth

Bluetooth provides short-range wireless connectivity with variants suited to continuous low-power streaming or burst data transmission. Its IoT applications include building, industrial, healthcare, and location services.

  • 2) Bluetooth: Bluetooth connects devices over short-range radio using 1 MHz channels in the 2.402–2.480 GHz ISM band.The Bluetooth standard defines radio, link, manager, baseband, and adaptation components.
  • 2) Bluetooth: BLE supports continuous data streaming with 125 kbps–2 Mbps rates, 1–100 mW power levels, and robust frequency-hopping spread spectrum across 40 channels.Bluetooth BR/EDR instead supports burst transmission at 1–3 Mbps.
  • 2) Bluetooth: Bluetooth is used for smart-building and industrial control, automation, indoor navigation, asset tracking, space utilization, and point-of-interest services.BLE was identified as the most suitable short-range communications solution in healthcare.
  • 2) Bluetooth: Short-range technologies such as Bluetooth, ZigBee, and WiFi do not meet current IoT demands for network range, capacity, and power efficiency.This limitation motivates the design of technologies with wider coverage and improved scalability.

B. LONG-RANGE M2M WIRELESS TECHNOLOGIES

Long-range M2M technologies are motivated by IoT requirements for long coverage, capacity, low data rates, low power, and affordable devices. LPWA addresses these requirements through scalable, power-optimized wide-area networking.

  • B. LONG-RANGE M2M WIRELESS TECHNOLOGIES: IoT applications require long-distance coverage, high network capacity, low data rates, low power consumption, and affordable devices.These requirements motivate alternatives to short-range M2M technologies and inefficient legacy solutions.
  • B. LONG-RANGE M2M WIRELESS TECHNOLOGIES: LPWA networks bridge local wireless and mobile wide-area technologies and are designed for modern IoT devices and applications.The survey describes LPWA as a potential solution for M2M communications.
  • B. LONG-RANGE M2M WIRELESS TECHNOLOGIES: LPWA offers tens-of-kilometers connectivity through optimized long-range coverage and supports battery operation for several years through sleep-mode power management.The paper also describes low data rates and power-optimized radio operation as core characteristics.
  • B. LONG-RANGE M2M WIRELESS TECHNOLOGIES: LPWA targets large deployments through high-capacity, scalable networks that may connect hundreds of thousands of devices to a base station.Ultra narrow band communication is identified as one technique for supporting many devices.
  • B. LONG-RANGE M2M WIRELESS TECHNOLOGIES: LPWA providers use diverse PHY and MAC specifications, while standardization efforts seek to enable communication across these technologies.The survey examines LoRaWAN, SigFox, RPMA, Telensa, and NB-IoT.

1) LoRaWAN

LoRa is a long-range, low-power physical-layer technology, while LoRaWAN connects battery-powered devices to network servers through gateways in a star-of-stars topology. Its operation uses adaptive spectrum and data-rate choices to balance quality of service, capacity, and battery life.

  • 1) LoRaWAN: LoRa provides more than 10 km coverage using spread-spectrum modulation designed for robust long-range communication.
  • 1) LoRaWAN: LoRaWAN connects battery-powered end devices to a central network server through gateways in a star-of-stars topology.Devices communicate with one or more gateways over single-hop LoRa or FSK, while gateways connect to servers through IP.
  • 1) LoRaWAN: Adaptive data rates and frequency selection let LoRa devices adjust communication conditions while supporting data rates from 0.3 kbps to 50 kbps.Sub-band selection and combination affect quality of service, network capacity, and device battery life.
  • 1) LoRaWAN: A particle-filter-based retransmission control algorithm was proposed alongside pure ALOHA to mitigate interference.
  • 1) LoRaWAN: LoRaWAN defines three bidirectional device classes with different downlink reception patterns and power requirements.Class A minimizes power, Class B adds scheduled receive windows, and Class C keeps receive windows open except during transmission.

2) SigFox

SigFox is a proprietary ultra-narrowband LPWA technology using public spectrum, very low data rates, small payloads, and long range. The surrounding comparison shows that LPWA technologies involve trade-offs among range, power, licensing, throughput, reliability, and spectrum constraints.

  • 2) SigFox: SigFox uses UNB modulation to send 100 Hz-wide messages at 100 or 600 bps over 10–50 km, with payload limits of 12 bytes uplink and 8 bytes downlink.Messages take an average of 2 s to reach the base station.
  • 2) SigFox: SigFox improves interference resistance through time, frequency, and space diversity, and devices can connect to any of three base stations in range.
  • 2) SigFox: RPMA uses the global 2.4 GHz ISM band and DSSS, providing up to 624 kbps uplink and 156 kbps downlink but higher energy consumption than LoRa and SigFox.Its drawbacks include 2.4 GHz interference and regional power limitations.
  • 2) SigFox: NB-IoT reduces data rates to no higher than 158.5 kbps uplink and 106 kbps downlink to reduce device cost and battery consumption.Release 14 adds localization, mobility, multicast, coverage, and other improvements while retaining Release 13 merits.
  • 2) SigFox: Unlicensed LPWA systems can face a 1% duty-cycle limit in the EU 868 ISM band, restricting each end device to at most 36 s/h of transmission.
  • 2) SigFox: Low-power operation does not necessarily mean low energy use, because low LPWA data rates can require more energy per transmitted bit.RPMA is cited as an example of higher power consumption from operating in the 2.4 GHz ISM band.
  • 2) SigFox: Most unlicensed LPWA technologies can provide reliable Sub-GHz communication, while licensed systems do not necessarily provide higher data rates.LoRaWAN, SigFox, and Telensa are described as reliable and robust; RPMA is reported at 624 kbps and NB-IoT at 158.5 kbps.

III. MARKET OPPORTUNITIES

LPWA has attracted substantial industrial and market interest, with deployments, investment, and M2M connection shares expected to grow rapidly. Forecasts position LPWA as a major alternative for IoT connectivity alongside established cellular generations.

  • III. MARKET OPPORTUNITIES: Telensa has deployed more than nine million devices across 30 countries, with smart lighting, parking, and tracking among its main use cases.
  • III. MARKET OPPORTUNITIES: 25.1 billion IoT units and $3.9 trillion in investment were forecast for 2021, with IoT applications expected to earn $4.3 trillion by 2024.The 2021 forecast represents 32% CAGR from 2016, and NB-IoT was expected to connect over 3 billion devices by 2023.
  • III. MARKET OPPORTUNITIES: LPWA’s global M2M connection share is expected to rise from 7% in 2016 to 31% by 2021, compared with 2G, 3G, and 4G+.The trend indicates that mobile operators are seeking alternatives to cellular networks for M2M connectivity.
  • III. MARKET OPPORTUNITIES: North America and Western Europe were expected to lead LPWA adoption by 2021, with projected shares of 31% and 20%, respectively.4G’s high data rates, low delays, and strict security were not expected to prevent LPWA deployment in the M2M segment.

IV. NEED FOR HORIZONTAL INTEGRATION AMONG LPWA TECHNOLOGIES

LPWA diversity creates interoperability complexity because technologies differ across radio, protocol, security, and service mechanisms. The paper therefore motivates convergence layers and greater compatibility among solutions.

  • IV. NEED FOR HORIZONTAL INTEGRATION AMONG LPWA TECHNOLOGIES: Diversity across LPWA bands, modulation, MAC, payload, communication, FEC, and security mechanisms complicates interoperability.These differences arise partly because many solutions were industry-designed for specific market demands without standardization.
  • IV. NEED FOR HORIZONTAL INTEGRATION AMONG LPWA TECHNOLOGIES: LoRa, SigFox, Telensa, and RPMA make different physical-layer choices, producing distinct coverage, interference, and propagation trade-offs.SigFox and Telensa use UNB variants, LoRa uses CSS, and RPMA operates in the global 2.4 GHz band.
  • IV. NEED FOR HORIZONTAL INTEGRATION AMONG LPWA TECHNOLOGIES: Technology-specific constraints limit suitable deployments, including RPMA’s battery unsuitability, SigFox’s traffic and regulatory limits, and missing QoS guarantees.In the US, SigFox’s approximate 2 s on-air time exceeds the 0.4 s regulatory maximum described in the paper.
  • IV. NEED FOR HORIZONTAL INTEGRATION AMONG LPWA TECHNOLOGIES: IPv6 and CoAP are proposed as convergence-layer candidates, but security and identity management still require additional work for IoT devices.WiSUN already supports IPv6 through 6LoWPAN, while IoT devices remain protected differently from computers.
  • IV. NEED FOR HORIZONTAL INTEGRATION AMONG LPWA TECHNOLOGIES: Unlicensed-band duty-cycle restrictions constrain LPWA channel occupancy, with SigFox, Telensa, and LoRa limited to 1% in the EU 868 ISM band.The paper computes a maximum transmission time of 36 s/h per end device in each EU 868 ISM sub-band.

V. LPWA SUITABILITY FOR IOT APPLICATION AND SERVICE USE-CASES

LPWA suitability depends on application requirements for bitrate, mobility, latency, coverage, capacity, security, and energy efficiency. The paper maps these requirements to different technologies across healthcare, transportation, agriculture, smart cities, metering, and automation.

  • V. LPWA SUITABILITY FOR IOT APPLICATION AND SERVICE USE-CASES: LPWA recommendations are based on each use-case’s bitrate, mobility, and real-time communication requirements, alongside coverage, capacity, security, cost, and energy efficiency.The recommendations are limited to the technical parameters listed in Table 2.
  • V. LPWA SUITABILITY FOR IOT APPLICATION AND SERVICE USE-CASES: Table 3 summarizes the paper’s recommended LPWA technologies for major IoT use-cases.The recommendations cover the use-case categories discussed in the section.
  • V. LPWA SUITABILITY FOR IOT APPLICATION AND SERVICE USE-CASES: For smart houses and industry, any LPWA technology can support periodic reports, but RPMA and NB-IoT are needed for video surveillance.LoRaWAN is inappropriate for video surveillance because of its low data rate; industrial two-way control can use LoRaWAN, RPMA, or NB-IoT.
  • V. LPWA SUITABILITY FOR IOT APPLICATION AND SERVICE USE-CASES: Healthcare favors NB-IoT and LoRaWAN for network capacity and range, with 53,547+ versus 40,000 nodes and 15 km versus 5 km urban range, respectively.RPMA and NB-IoT can additionally support real-time video monitoring, while SigFox is excluded from some medical services.
  • V. LPWA SUITABILITY FOR IOT APPLICATION AND SERVICE USE-CASES: Transportation requires high-throughput, reliable, real-time, bidirectional communication, making RPMA and NB-IoT preferable while LoRaWAN is unsuitable.The paper attributes LoRaWAN’s mismatch to delay, jitter, and ALOHA contention constraints.
  • V. LPWA SUITABILITY FOR IOT APPLICATION AND SERVICE USE-CASES: Agriculture and environmental monitoring favor LoRaWAN, SigFox, and Telensa for periodic or event-driven messages, while real-time control excludes SigFox and Telensa.NB-IoT is limited by cellular availability in outskirts, and RPMA by high power consumption for remote nodes.

VI. CHALLENGES AND FUTURE RESEARCH DIRECTIONS

LPWA networks face unresolved challenges involving security, scalability, spectrum use, service support, reliability, cost, mobility, and data processing. The survey organizes existing research and identifies directions for addressing these limitations.

  • Security and privacy: LPWA security remains challenging because massive device populations complicate authentication and encryption, while cloud-dependent processing raises further concerns for privacy-sensitive applications.Healthcare deployments are specifically identified as requiring mandatory privacy protection.
  • Deployment and economics: LPWA operators must minimize service subscription costs, while mobility support still requires capabilities such as secure communication, inter-operator billing, and device location.
  • Service support: LPWA must expand beyond delay- and loss-tolerant services, because applications such as video surveillance require higher data rates and larger payloads.RPMA and NB-IoT are described as tentative solutions, but higher-rate communication remains necessary.
  • Data handling: Low data rates and small frame sizes make classical compression inefficient, creating a need for more robust application-layer compression techniques.CoIP is cited as one proposed application-layer approach.
  • Radio operation and reliability: Interference, spectrum management, and message integrity remain concerns as shared-spectrum deployments grow and licensed technologies require frequency licensing and management.LoRa interference can worsen with increasing device counts, while LPWA systems also face downlink integrity limitations.

14 NB-IoT

The survey identifies scalability as a serious concern for LPWA deployments as device populations increase. For LoRa, the number of end devices has a greater effect on scalability than spectrum restrictions.

  • 14 NB-IoT: The number of LPWA devices is expected to increase exponentially, making scalability a serious challenge.
  • 14 NB-IoT: LoRa offers configurable frequency, spreading factor, bandwidth, and coding-rate options but still limits the number of supported transmitters.

VII. CONCLUSION

The survey argues that LPWA deployment should account for integration among diverse technologies and differing IoT use cases. It also compares research efforts, discusses market contributions, and identifies unresolved challenges with recommendations for future work.

  • VII. CONCLUSION: The survey argues that integration among diverse LPWA technologies is needed and recommends effective solutions for different IoT use cases.
  • VII. CONCLUSION: It compares and classifies recent research on LPWA operation, discusses market and business contributions, and presents recommendations for addressing remaining challenges.

ACRONYMS

The acronyms section lists abbreviations used throughout the LPWA survey, including networking, authentication, modulation, and communication terms.

  • ACRONYMS: The acronym list includes LPWA-related networking, security, modulation, and communication abbreviations such as AAA, BLE, CID, CoAP, CRC, CSMA/CA, CSS, and DSSS.
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