5. Wireless Technologies and Standards

Introduction and Context

The Internet of Things (IoT) is not supported by a single wireless technology. It is a heterogeneous communication environment in which sensors, actuators, gateways, mobile devices, cloud platforms, industrial systems, and satellites exchange data under very different constraints. A wearable medical sensor may require only a few kilobits per second but must operate for months on a small battery. A robotic vehicle may require high throughput and millisecond-level latency. A smart meter may transmit a small message several times a day from a location where wired connectivity is impractical. Selecting one technology for all these situations is therefore technically unsound.

Wireless selection is a systems-engineering decision. It must consider radio range, spectrum, throughput, latency, mobility, energy consumption, reliability, security, deployment model, device density, regulatory conditions, and total cost of ownership. These properties are interdependent. Higher data rates commonly require greater bandwidth and energy; long range may involve lower throughput; low latency may require denser infrastructure; and strong security may increase computational and management requirements.

This chapter evaluates major IoT wireless technologies and standards: Wi-Fi, Bluetooth Low Energy (BLE), Zigbee, Thread, RFID, NFC, ultra-wideband (UWB), LoRaWAN, Sigfox, NB-IoT, LTE-M, private cellular, 5G and emerging 6G concepts, mesh networking, and satellite IoT. The purpose is not to identify a universally superior technology, but to develop a rigorous basis for matching communication capabilities to application requirements.

Learning Objectives

By the end of this chapter, the reader should be able to:

1. Explain the principal operating characteristics of major IoT wireless technologies.

2. Compare technologies according to coverage, throughput, latency, mobility, energy use, security, and cost.

3. Distinguish short-range, local-area, wide-area, cellular, mesh, and satellite connectivity.

4. Select an appropriate technology or hybrid architecture for a stated IoT scenario.

5. Critically evaluate trade-offs involving spectrum, infrastructure, reliability, and lifecycle cost.

6. Discuss security, privacy, regulatory, and governance issues in wireless IoT deployments.

7. Identify emerging research directions in private cellular, 5G/6G, edge intelligence, and satellite IoT.

A Framework for Comparing Wireless Systems

A useful comparison begins by separating the communication problem into several dimensions. Coverage describes the physical and practical area served by a link or network. A short-range system may be ideal inside a room, whereas a low-power wide-area network (LPWAN) is intended for kilometres of coverage and small payloads. Coverage is affected by frequency, antenna design, transmit power, building materials, terrain, and network density.

Throughput is the data rate available to an application. It should not be confused with useful application capacity, because protocol overhead, retransmissions, contention, and duty-cycle restrictions reduce effective throughput. Latency is the time between transmission and successful delivery, including processing and queuing. A technology can have a high nominal rate but poor latency under congestion.

Mobility concerns whether devices can move while maintaining service and whether the network supports handover. Energy efficiency includes radio power, sleep behaviour, connection maintenance, retransmission, and the energy required by security operations. Battery life depends on traffic patterns rather than on radio specifications alone.

Security includes authentication, confidentiality, integrity, key management, secure commissioning, firmware protection, and resistance to jamming and denial of service. Cost includes modules, antennas, gateways, spectrum or subscription fees, installation, maintenance, cloud services, security operations, and eventual replacement. A low-cost radio can create a high-cost deployment if it requires extensive gateways or manual maintenance.

A practical decision can be represented as a weighted utility model:

U(t) = Σ wi si(t) − Σ cj rj(t)

where t is a candidate technology, si are scored performance dimensions, wi are application-specific weights, rj are risks or penalties, and cj are their importance. This is not a substitute for engineering tests, but it makes assumptions visible. Doctoral analysis should also examine uncertainty: radio performance measured in a laboratory may differ significantly in a metal-clad factory, underground facility, or dense urban environment.

Personal- and Local-Area Technologies

Wi-Fi

Wi-Fi, standardized principally through the IEEE 802.11 family, provides relatively high throughput and mature IP connectivity. It is widely deployed in homes, campuses, offices, hospitals, and industrial sites. Modern generations improve spectral efficiency, multi-user operation, power management, and operation in dense environments. Wi-Fi is appropriate for cameras, building controllers, appliances, augmented-reality devices, and gateways that need substantial bandwidth.

Its limitations include comparatively high energy consumption for small battery devices, variable performance under contention, and dependence on access-point infrastructure. Wi-Fi HaLow, based on operation in sub-gigahertz spectrum, extends coverage and improves penetration for IoT, although ecosystem availability and regional spectrum rules must be considered. Security should use current WPA3 capabilities where supported, with strong credentials, network segmentation, protected management frames, and controlled onboarding.

Bluetooth Low Energy

BLE is designed for short-range communication with low power consumption. Devices generally advertise, discover, and establish brief connections rather than maintaining a continuously active high-power link. BLE supports sensors, wearables, medical devices, asset tags, beacons, and commissioning of other IoT equipment. Its low energy use results from short packets, sleeping behaviour, and efficient connection events.

BLE traditionally uses a central-peripheral relationship, but Bluetooth Mesh enables many-to-many communication through managed flooding and relaying. BLE offers practical interoperability through standardized profiles, though application-specific profiles may still create integration difficulties. Security depends heavily on pairing method, key storage, privacy settings, and protection against unauthorized proximity-based access. BLE is not normally the first choice for long-range backhaul or high-volume video.

Zigbee and Thread

Zigbee is a low-power networking technology commonly used in home and building automation. It supports star and mesh arrangements, allowing routers to relay messages and extend coverage. Zigbee networks typically include end devices, routers, and a coordinator or border function. The technology is well suited to lighting, environmental sensing, switches, and low-rate control.

Thread is an IPv6-based, low-power mesh networking technology built for reliable device-to-device communication in homes and buildings. It uses 6LoWPAN adaptation over IEEE 802.15.4 radios and normally connects to other IP networks through a Thread Border Router. Thread separates the mesh network from application-layer semantics, allowing protocols such as Matter to operate above it. This is a significant architectural distinction: Thread is primarily a network technology, whereas an application protocol defines device behaviour and interoperability.

Mesh systems can improve coverage and resilience, but they introduce routing overhead, topology-management issues, and dependence on mains-powered routers. A poorly planned mesh may suffer from hidden nodes, excessive hop counts, interference, or a single vulnerable border router. Secure commissioning and lifecycle key management are essential.

RFID, NFC, and UWB

RFID identifies objects through radio tags and readers. Passive RFID tags obtain operating energy from the reader field, allowing inexpensive labels for inventory, access control, logistics, and library systems. Active or battery-assisted tags provide greater range and sensing capability. RFID is primarily an identification and event-detection technology, not a general-purpose IP network.

NFC is a very short-range technology used for contactless payments, access credentials, device pairing, and product interaction. Its intentional proximity requirement can reduce accidental communication, but it does not eliminate relay attacks, malicious tags, privacy risks, or compromised readers. Secure elements, tokenization, mutual authentication, and transaction controls are important in sensitive applications.

UWB uses very wide bandwidth and precise time-of-flight techniques to provide accurate ranging and localization. It is valuable in indoor positioning, access systems, industrial asset tracking, and secure ranging applications. UWB can achieve substantially better positioning precision than many conventional low-power radios, but deployment requires suitable anchors, calibrated environments, compatible devices, and careful interference and security analysis.

Low-Power Wide-Area Networking

LPWAN technologies address devices that send small amounts of data over long distances while operating for extended periods on batteries. They generally trade throughput and continuous interactivity for coverage and energy efficiency.

LoRaWAN

LoRaWAN is a network protocol commonly using LoRa physical-layer modulation. End devices communicate with gateways, which forward packets to network servers. The architecture is often described as a star-of-stars rather than a conventional routed mesh. This structure simplifies large-area deployment and allows multiple gateways to hear the same transmission, improving reception opportunities.

LoRaWAN supports low-power sensing, adaptive data rate, bidirectional communication, device classes with different downlink availability, and public or private deployments. It is useful for agriculture, environmental monitoring, metering, parking, and municipal sensing. Constraints include low payload capacity, duty-cycle or spectrum regulations in some regions, limited suitability for frequent downlink traffic, and variable performance in congested or obstructed environments. Security uses separate network and application security concepts, but secure key provisioning and protection of end-device credentials remain operational responsibilities.

Sigfox

Sigfox was designed for very small, infrequent messages using an operator-managed ultra-narrowband LPWAN model. Its advantages traditionally include low device complexity, low energy use, and broad-area service where an operator network is available. Its limitations include very small payloads, restricted downlink capability, limited application flexibility, and dependence on commercial network coverage and business sustainability. The technology illustrates an important principle: low hardware cost does not guarantee long-term service availability or organizational control.

Cellular IoT and Private Networks

NB-IoT and LTE-M

NB-IoT is a 3GPP cellular technology optimized for low-rate, power-sensitive devices requiring wide-area coverage. It offers deep coverage, managed quality of service, and integration with operator infrastructure. It is suitable for meters, fixed sensors, alarms, and devices that transmit modest data volumes. Its mobility and latency characteristics are less suitable for rapidly moving or interactive applications, and deployment may depend on operator support and subscription arrangements.

LTE-M provides higher throughput and lower latency than NB-IoT, with better support for mobility, voice-related capabilities in some implementations, and firmware updates. It is appropriate for connected transport, wearables, alarms, asset tracking, and mobile industrial equipment. Its module and service costs may be greater than those of simpler LPWAN alternatives, but the additional capability can reduce application constraints.

Both technologies benefit from cellular-grade authentication, managed spectrum, standardized security procedures, and broad operator expertise. They still require secure application design, device identity management, patching, and protection against compromised endpoints. Cellular security is not a complete substitute for IoT security engineering.

Private Cellular and 5G

Private cellular networks use dedicated or locally controlled infrastructure and spectrum to serve an enterprise, campus, port, mine, utility, or factory. They can provide predictable coverage, traffic isolation, mobility, quality of service, and integration with edge computing. Compared with Wi-Fi, private cellular may offer more structured mobility and admission control; compared with public cellular, it can provide greater organizational control.

5G introduces enhanced broadband, massive machine-type communication, and ultra-reliable low-latency communication as broad usage categories. Features such as network slicing, edge computing, time-sensitive networking integration, and advanced positioning are relevant to industrial IoT. However, advertised 5G capability is not automatically realized by every deployment. Actual results depend on spectrum, radio configuration, core architecture, backhaul, device support, and service-level engineering.

The business case for private cellular must include spectrum licensing, radio and core equipment, integration, specialist skills, cybersecurity operations, and lifecycle upgrades. It is most compelling where mobility, deterministic performance, large scale, or operational isolation justify the investment.

6G Directions

6G remains a research and standardization domain rather than a universally available commercial technology. Proposed directions include integrated sensing and communication, AI-native network control, extremely high-frequency operation, joint communication and localization, semantic communications, and tighter integration with non-terrestrial networks. These concepts may support digital twins, autonomous systems, and high-precision industrial applications.

Research claims should be evaluated cautiously. Higher frequencies can provide greater bandwidth but suffer from propagation loss and blockage. AI-based control may improve resource allocation while increasing explainability, data-governance, and attack-surface concerns. The central research question is not simply whether 6G will be faster, but how communication, sensing, computation, and control will be co-designed.

Mesh, Non-Terrestrial, and Hybrid Architectures

Mesh networking is a topology and routing approach rather than a single radio standard. In a mesh, nodes may forward traffic for others. Mesh can reduce dependence on a single access point and extend coverage, but each additional hop introduces delay, energy use, routing complexity, and possible failure. Mesh is particularly valuable where infrastructure is difficult to install, yet it is not automatically more reliable than a star network.

Satellite IoT connects sensors through low-earth-orbit, geostationary, or other satellite systems. It is valuable for oceans, remote agriculture, pipelines, disaster response, logistics, and environmental observation. Low-earth-orbit systems can reduce latency relative to geostationary systems, but coverage, terminal power, antenna visibility, subscription cost, and intermittent availability must be assessed. Satellite links are generally best for small, delay-tolerant messages unless specialized services are used.

Hybrid architectures combine technologies. A BLE sensor may communicate with a Wi-Fi or cellular gateway; a LoRaWAN network may forward data through fiber or satellite; a private 5G system may use UWB for precise positioning; and a remote asset may use local sensing with satellite backhaul. Hybrid design separates local access from wide-area transport and often produces a better outcome than forcing one technology to perform every function.

Comparative Decision Matrix

No matrix can replace field testing, but the following qualitative pattern is useful. Wi-Fi offers high throughput, moderate range, moderate latency, moderate-to-high energy use, and low-to-moderate deployment cost. BLE offers low-to-moderate throughput, short range, low energy use, and low module cost. Zigbee and Thread offer low throughput, low energy operation, and mesh-based building coverage. RFID and NFC provide very short-range identification or interaction with minimal tag energy requirements. UWB offers moderate data communication with exceptional ranging capability but higher infrastructure complexity.

LoRaWAN and Sigfox provide long range, low throughput, low energy use, and generally low device cost, but limited downlink and application capacity. NB-IoT provides wide coverage, low-to-moderate throughput, strong operator-managed infrastructure, and low-to-moderate device energy use. LTE-M improves mobility, latency, and throughput. Private cellular and 5G offer high capability and mobility at higher infrastructure and management cost. Satellite IoT provides the broadest geographic reach where terrestrial networks are unavailable, but normally at greater service cost and with constrained energy and latency characteristics.

Applications and Professional Decision-Making

Technology selection should begin with an application profile rather than brand preference. The designer should define payload size and frequency, acceptable delay, geographic area, indoor or outdoor conditions, mobility, expected battery life, device density, data criticality, installation access, security obligations, and operational lifetime. A prototype should measure packet delivery, latency distributions, energy per successful message, coverage margins, and recovery after outages.

For smart buildings, Thread or Zigbee may support lighting and environmental control, while Wi-Fi serves cameras and high-bandwidth appliances. BLE can provide occupancy or wearable sensing, and UWB can support access and location services. For a regional water utility, LoRaWAN may suit fixed meters where gateways can be installed; NB-IoT may be preferred where operator coverage and managed service are more valuable. For a mining operation, private cellular can support mobile machines and critical telemetry, with UWB for positioning and satellite as a backup for remote sites.

Operational architecture matters as much as radio choice. Gateways should be minimized where possible, but they must be hardened, monitored, and remotely updated. Edge processing can filter data, detect anomalies, and reduce backhaul. Analytics can identify declining signal quality, abnormal retransmissions, battery depletion, or suspicious traffic. Machine-learning models should not obscure safety decisions; critical control logic requires deterministic safeguards and human accountability.

Illustrative Case Study: Connected Cold-Chain Logistics

Background

A fictional pharmaceutical distributor operates refrigerated containers moving between warehouses, airports, and regional clinics. Each container requires temperature, humidity, door-state, and location monitoring. Pharmaceutical quality rules require evidence that temperature remained within a defined range, while logistics managers need alerts when a shipment is delayed or mishandled.

Situation and Analysis

A Wi-Fi-only design fails because containers spend much of their journey outside access-point coverage. A BLE-only design offers low energy consumption but requires nearby gateways. LoRaWAN could provide long-range sensor communication around distribution centres, but continuous wide-area mobility and dependable roaming are not guaranteed. NB-IoT or LTE-M provides wide-area cellular service; LTE-M is more appropriate if mobility, firmware updates, and more interactive communication are required. Satellite IoT may be necessary for ocean routes or regions without terrestrial coverage.

Approach

The distributor selects BLE sensors inside each container, an LTE-M gateway for normal wide-area connectivity, and satellite fallback for routes with unreliable cellular service. The gateway stores data during outages, sends threshold alarms promptly, and uploads a signed historical record when connectivity returns. Device identities are provisioned before deployment, keys are stored in protected hardware where feasible, and the cloud platform separates operational users from auditors. Temperature alarms are processed at the edge so that a temporary cloud outage does not prevent local notification.

Outcome

The hybrid design reduces sensor energy consumption, supports mobility, and avoids equipping every low-power sensor with a cellular modem. Its cost is higher architectural complexity. The organization therefore establishes gateway replacement procedures, cellular and satellite service monitoring, certificate rotation, and periodic coverage tests.

Learning Points

The case demonstrates that the best design may use several radios, each performing a distinct role. It also shows why availability, evidence integrity, and operational recovery can be more important than peak throughput. A technology should be judged against the complete lifecycle and regulatory context, not only its module price.

Risks, Limitations, and Common Errors

A frequent mistake is selecting a radio from its nominal range or data rate without testing the actual environment. Metal structures, foliage, interference, antenna orientation, and installation height can radically change performance. Another error is treating battery life as a fixed property of a protocol. Reporting intervals, retransmissions, connection duration, temperature, and firmware-update strategy may dominate energy consumption.

Interoperability is also frequently overstated. Standards may define radio behaviour while leaving application models, provisioning, cloud APIs, or device semantics to vendors. Vendor lock-in can emerge through proprietary gateways, management platforms, or subscription contracts. A procurement process should require exportable data, documented interfaces, security-update commitments, and an exit strategy.

Wireless systems are exposed to eavesdropping, spoofing, replay, jamming, rogue devices, traffic analysis, and denial of service. Security controls should include unique identities, authenticated commissioning, least privilege, encrypted communication, secure boot, signed firmware, key rotation, logging, segmentation, vulnerability management, and end-of-life decommissioning. Privacy analysis is essential where location, occupancy, health, or behavioural data are collected.

Regulatory compliance includes spectrum rules, radio certification, electromagnetic exposure requirements, data protection, critical-infrastructure obligations, and sector-specific rules. Governance must define who owns device identities, who may change configurations, how incidents are reported, and how long data are retained. Ethical design requires proportional data collection, accessibility, transparency, and safeguards against unjustified surveillance.

Emerging Directions and Best Practices

Current development is moving toward convergence rather than replacement. Matter and related application ecosystems seek to improve interoperability across local technologies. Edge computing reduces latency and backhaul dependence. Open radio access networks may alter cellular deployment economics, while integrated sensing and communication may allow networks to locate objects as well as transport data. Satellite-terrestrial integration is expanding the geographic continuity of IoT services.

Best practice is to:

• translate application needs into measurable communication requirements;
• evaluate at least two technically credible alternatives;
• test in representative physical and interference conditions;
• design commissioning, updates, monitoring, and retirement before deployment;
• separate application security from assumptions about radio security;
• use hybrid architectures when local sensing and wide-area transport have different requirements;
• calculate total cost of ownership and service dependency;
• document uncertainty, failure modes, and recovery procedures.

Chapter Summary

IoT wireless technologies occupy different positions in the design space. Wi-Fi provides high local throughput; BLE provides efficient short-range sensing; Zigbee and Thread support low-power building meshes; RFID and NFC enable identification and intentional proximity interactions; UWB adds precise ranging. LoRaWAN and Sigfox provide low-rate wide-area communication, while NB-IoT and LTE-M bring cellular coverage and managed service characteristics. Private cellular and 5G support mobility, quality of service, and industrial control at greater cost. Mesh networking improves reach in some environments but adds routing complexity, and satellite IoT extends connectivity to remote areas with energy, latency, and cost trade-offs.

Selection must be based on a multidimensional analysis of coverage, throughput, latency, mobility, energy, security, reliability, regulation, and lifecycle cost. Hybrid architectures are often superior because they assign local access, gateway processing, and wide-area transport to technologies suited to each role. Secure provisioning, monitoring, updates, privacy protection, and operational governance are as important as radio performance. Emerging systems increasingly combine communication, positioning, sensing, edge computing, AI, and satellite connectivity.

Key Terms

Coverage: Geographic area in which a communication service can operate with acceptable performance.

Throughput: Useful data successfully delivered per unit of time.

Latency: Time required for data to travel from source to destination and be processed.

Mobility: Ability of a device to move while maintaining communication service.

LPWAN: Low-power wide-area networking designed for long-range, low-rate communication.

Mesh network: Network in which nodes can relay traffic for other nodes.

Gateway: Device that connects one network or protocol domain to another.

BLE: Bluetooth technology optimized for low-power short-range communication.

Thread: IPv6-based low-power mesh networking technology using IEEE 802.15.4 radios.

RFID: Radio-frequency identification using readers and electronic tags.

NFC: Very short-range wireless technology for proximity communication and identification.

UWB: Wideband radio technology capable of highly precise ranging and localization.

LoRaWAN: LPWAN protocol supporting low-power communication through gateways and network servers.

NB-IoT: Cellular IoT technology optimized for low-rate, wide-area device communication.

LTE-M: Cellular IoT technology supporting greater mobility, throughput, and interactivity than NB-IoT.

Private cellular: Locally controlled cellular network serving a defined organization or site.

Network slicing: Logical partitioning of network resources to support differentiated services.

Secure boot: Startup process that permits only authenticated software to execute.

Total cost of ownership: All acquisition, operation, maintenance, service, security, and retirement costs.

Non-terrestrial network: Communication network using satellites or other airborne platforms.

Review Questions

Short Answer Questions

1. Why is nominal throughput insufficient for comparing IoT wireless technologies?

2. Distinguish Thread from an application-layer protocol such as Matter.

3. What makes UWB valuable in addition to ordinary data communication?

4. State two operational differences between NB-IoT and LTE-M.

5. Why can mesh networking increase both resilience and complexity?

Long Answer Questions

1. Explain a multidimensional framework for selecting an IoT wireless technology.

2. Compare Wi-Fi, BLE, Zigbee, and Thread for a smart-building deployment.

3. Evaluate LoRaWAN, Sigfox, NB-IoT, and LTE-M for regional asset monitoring.

4. Discuss the security and governance responsibilities that remain even when cellular infrastructure is used.

5. Explain the technical and economic rationale for private cellular and 5G in industrial IoT.

Analytical / Application Questions

1. Design a hybrid communication architecture for a remote agricultural operation containing battery-powered sensors, mobile machinery, and intermittent backhaul.

2. A hospital needs indoor asset location, wearable monitoring, high-definition video, and secure access control. Select suitable technologies and justify the combination using the chapter’s evaluation dimensions.

3. Critically assess whether satellite IoT should be the primary or backup link for a global logistics organization. Identify the assumptions that would affect your decision.

22. Multiple Choice Questions with Answers

Question 1

A battery-powered environmental sensor sends a few bytes every hour from a rural area. Which technology is generally the most appropriate starting point?

A. UWB

B. LoRaWAN

C. Wi-Fi

D. NFC

Correct Answer: B. LoRaWAN

Question 2

Which characteristic most clearly distinguishes LTE-M from NB-IoT?

A. LTE-M generally provides better mobility and higher throughput

B. LTE-M is designed only for passive identification

C. LTE-M cannot operate over cellular infrastructure

D. LTE-M requires a mesh of battery-powered routers

Correct Answer: A. LTE-M generally provides better mobility and higher throughput

Question 3

In a Thread deployment, what is the principal role of a Thread Border Router?

A. To replace every end device’s battery

B. To provide UWB positioning

C. To connect the Thread mesh to other IP networks

D. To convert RFID tags into satellite terminals

Correct Answer: C. To connect the Thread mesh to other IP networks

Question 4

Why might a hybrid BLE and LTE-M architecture be preferred for mobile cold-chain containers?

A. BLE provides local low-power sensing while LTE-M provides wide-area mobility

B. BLE supplies satellite coverage and LTE-M supplies passive identification

C. Both technologies eliminate the need for security management

D. LTE-M is used only when devices never move

Correct Answer: A. BLE provides local low-power sensing while LTE-M provides wide-area mobility

Question 5

Which technology is especially appropriate when precise indoor ranging is a primary requirement?

A. Sigfox

B. UWB

C. NB-IoT

D. RFID only

Correct Answer: B. UWB

Question 6

Which statement best describes a major limitation of LPWAN technologies such as LoRaWAN and Sigfox?

A. They are generally optimized for high-volume video

B. They require a wired connection for every sensor

C. They trade high throughput and frequent downlink for range and energy efficiency

D. They cannot support outdoor deployments

Correct Answer: C. They trade high throughput and frequent downlink for range and energy efficiency

Question 7

What is a significant advantage of private cellular networks in industrial environments?

A. They remove all infrastructure and management costs

B. They can provide controlled coverage, mobility, and quality of service

C. They operate only at NFC range

D. They are limited to passive tags

Correct Answer: B. They can provide controlled coverage, mobility, and quality of service

Question 8

Which factor is most likely to make a mesh network more complex than a star network?

A. The need for routing and topology management across multiple hops

B. The absence of any intermediate nodes

C. The inability to relay messages

D. The requirement that all devices use satellite links

Correct Answer: A. The need for routing and topology management across multiple hops

Question 9

Which security practice is most directly concerned with preventing unauthorized firmware from executing during startup?

A. Adaptive data rate

B. Secure boot

C. Network slicing

D. Duty-cycle regulation

Correct Answer: B. Secure boot

Question 10

A remote ocean-monitoring system has no terrestrial coverage and sends small, delay-tolerant reports. Which option is most defensible?

A. Satellite IoT, while accounting for terminal energy and service cost

B. NFC, because it provides global coverage

C. Indoor Wi-Fi, because access points are unnecessary

D. UWB, because precise ranging solves backhaul availability

Correct Answer: A. Satellite IoT, while accounting for terminal energy and service cost