One of the most consequential decisions in a 5G Fixed Wireless Access (FWA) deployment is the choice of radio spectrum specifically, whether to deploy in millimeter wave (mmWave) bands above 24 GHz or in sub-6 GHz bands below 6 GHz. Each spectrum type imposes fundamentally different requirements on the CPE hardware, the installation process, and the network planning methodology. This article provides a structured comparison to help ISPs, system integrators, and telecom operators make informed CPE procurement decisions.
The Physics of the Two Spectrum Worlds
Sub-6 GHz 5G operates in bands such as n1 (2100 MHz), n3 (1800 MHz), n7 (2600 MHz), n28 (700 MHz), and n78 (3500 MHz). These frequencies propagate well through walls, foliage, and moderate obstacles, with typical outdoor-to-indoor penetration loss of 10-18 dB. A sub-6 GHz CPE installed indoors near a window can often achieve usable signal quality without external antenna mounting. Range is measured in kilometers: a well-engineered n78 deployment with 4×4 MIMO and 256QAM can serve customers 3-5 km from the cell site in suburban environments.
mmWave 5G operates in bands such as n257 (28 GHz), n258 (26 GHz), n260 (39 GHz), and n261 (28 GHz, US). At these frequencies, propagation is fundamentally different. Free-space path loss is 20-30 dB higher than sub-6 GHz at equivalent distance, outdoor-to-indoor penetration through modern energy-efficient windows can exceed 25-30 dB of loss, and even foliage or heavy rain can attenuate the signal. A single tree between the cell site and the CPE can reduce mmWave throughput by 50% or more. The practical range for mmWave FWA is typically 300-800 meters in urban deployments and requires near-line-of-sight conditions.
However, mmWave compensates for propagation challenges with raw bandwidth. A single n257 carrier in the 28 GHz band can be up to 400 MHz wide four times the maximum 100 MHz carrier width available in n78 sub-6 GHz. This translates directly into multi-gigabit peak throughput: commercial mmWave CPE devices routinely deliver 2-4 Gbps downlink under good signal conditions, compared to 500 Mbps to 1.5 Gbps for sub-6 GHz CPE in typical deployments.
CPE Hardware: Different Requirements, Different Designs
The physical design of mmWave CPE differs substantially from sub-6 GHz CPE due to the antenna requirements. mmWave devices use phased-array antenna modules typically 16 to 64 antenna elements arranged in a flat panel to achieve beamforming gain that compensates for path loss. These modules are physically larger than sub-6 GHz antennas and must be mounted with a clear, unobstructed view of the serving cell, which almost always requires outdoor installation.
Outdoor mmWave CPE, such as Honlly Telecom HL-880U series, integrates the phased-array antenna, modem, and networking electronics into a single IP67-rated enclosure designed for pole, wall, or rooftop mounting. Power is delivered via Power over Ethernet (PoE), and the indoor unit connects through a single Ethernet cable. This architecture eliminates the RF cable loss that would be incurred by a split indoor-outdoor design a critical advantage at mmWave frequencies where every decibel of loss matters.
Sub-6 GHz CPE offers more deployment flexibility. Indoor desktop CPE with integrated antennas can serve a significant portion of the coverage footprint, especially in the lower bands (n28, n3, n1) where building penetration is adequate. For edge-of-coverage or rural deployments, outdoor sub-6 GHz CPE with high-gain directional antennas (8-12 dBi) can extend range and improve signal quality, trading some installation simplicity for better performance.
Deployment Scenarios: When to Choose Which
Urban and dense suburban FWA. In neighborhoods where cell sites are spaced 500-800 meters apart and subscribers are concentrated, mmWave FWA delivers fiber-like speeds that can compete directly with cable broadband. The CPE cost is higher (typically 2-3x a comparable sub-6 GHz device), but the capacity advantage per sector makes it viable where subscriber density justifies the investment. Operators such as Verizon have deployed mmWave FWA to over 40 million households in the US using this model.
Suburban and rural broadband. Where cell site spacing exceeds 1-2 km, sub-6 GHz FWA is the practical choice. The longer range and better non-line-of-sight (NLOS) performance of sub-6 GHz bands particularly when combining low-band carriers (n28, 700 MHz) for coverage with mid-band carriers (n78, 3500 MHz) for capacity via carrier aggregation provides a more cost-effective solution for lower-density areas. A single n78 cell site can cover an area 10-25 times larger than a mmWave site, dramatically reducing infrastructure cost per subscriber.
Enterprise and industrial fixed wireless. For enterprise customers requiring symmetric multi-gigabit throughput think video production studios, data center interconnects, or campus backbone links mmWave is the preferred option when line-of-sight conditions exist. For enterprise applications where reliability and availability outweigh peak throughput (e.g., retail point-of-sale, branch office connectivity, backup WAN), sub-6 GHz CPE with dual-SIM failover provides a more resilient solution.
Cost Comparison: Total Cost of Ownership
The per-device cost comparison tells only part of the story. A comprehensive TCO analysis for FWA deployments should account for multiple factors:
- CPE unit cost: mmWave CPE typically ranges from USD 300-600 per unit, compared to USD 120-350 for sub-6 GHz CPE
- Installation cost: mmWave requires professional outdoor mounting at USD 150-400 per site, while sub-6 GHz can often be self-installed indoors (USD 50-200 for outdoor installs)
- Site survey requirements: Essential for mmWave line-of-sight verification; recommended for edge-of-coverage sub-6 GHz only
- Cell site density: mmWave requires 300-800m spacing with more sites needed; sub-6 GHz works with 1-5 km spacing
- Capacity per sector: mmWave delivers 4-8 Gbps supporting high subscriber density; sub-6 GHz delivers 1-3 Gbps for moderate density
Decision Framework: Five Questions to Guide Your Choice
- What is the target subscriber density? High-density urban areas with more than 500 potential subscribers per square kilometer favor mmWave. Rural areas with fewer than 50 subscribers per square kilometer almost always favor sub-6 GHz.
- What throughput SLA are you offering? If the service tier requires more than 500 Mbps downlink consistently, mmWave becomes the primary candidate. For service tiers up to 100-300 Mbps, sub-6 GHz is typically sufficient.
- Can you support professional truck-roll installations? If the business model relies on self-install, sub-6 GHz indoor CPE is the only practical option. mmWave FWA requires professional installation for antenna alignment and line-of-sight verification.
- What spectrum do you have access to? This is often the decisive factor. Operators with substantial mmWave holdings can deploy mmWave FWA. Operators with primarily sub-6 GHz spectrum will naturally deploy sub-6 GHz FWA, potentially augmenting with mmWave in high-demand urban hotspots.
- Is the deployment indoors or outdoors? Indoor CPE almost always operates in sub-6 GHz bands, as mmWave building penetration loss is prohibitive. Outdoor CPE can support either spectrum type, with the choice driven by the factors above.
The Hybrid Future: Multi-Band CPE
An emerging category of CPE combines sub-6 GHz and mmWave radios in a single device, using sub-6 GHz as an anchor for coverage and reliability while aggregating mmWave for capacity bursts. Qualcomm Snapdragon X80 modem-RF platform, announced in early 2026, supports concurrent sub-6 GHz + mmWave aggregation with intelligent traffic steering. While these multi-band devices currently command a premium, they represent a strategic option for operators planning long-term FWA infrastructure that can adapt to evolving spectrum availability and subscriber demand.
Frequently Asked Questions
Q: Can a single CPE support both mmWave and sub-6 GHz?
A: Yes, multi-band CPE devices with dual radio chains can support both spectrum types, though they are more expensive than single-band devices. These are increasingly common in the premium CPE segment and are well-suited for operators who want deployment flexibility across diverse coverage footprints.
Q: Does weather affect mmWave CPE performance?
A: Yes. Heavy rain causes attenuation of 5-10 dB/km at 28 GHz, snow accumulation on antenna enclosures, and even dense fog can reduce mmWave signal quality. Outdoor mmWave CPE should be specified with adequate link budget margin (typically 10-15 dB above the minimum usable signal) to maintain service during adverse weather conditions.
Q: Is sub-6 GHz 5G fast enough compared to mmWave?
A: For the vast majority of residential and small business FWA use cases, sub-6 GHz 5G delivering 100-500 Mbps is more than adequate supporting 4K streaming, video conferencing, cloud applications, and multiple simultaneous users. mmWave becomes relevant when service tiers exceed 500 Mbps or when very high per-sector capacity is needed to serve dense subscriber concentrations.
Looking for CPE solutions optimized for your spectrum strategy? Honlly Telecom supplies both sub-6 GHz and mmWave-ready CPE devices for fixed wireless access deployments worldwide, with carrier-grade TR-369 management and flexible OEM customization options. Contact our team to discuss your requirements.