What is the FR2 band in 5G NR and what are the defined operating bands?
5G NR FR2 Bands
FR2 represents the high-capacity, high-frequency layer of the 5G NR standard, designed for multi-Gbps throughput in dense deployments.
Technical Considerations
(1) n257 (26.5-29.5 GHz): 3 GHz total bandwidth. Divided among operators in 100-800 MHz blocks. Korea: SK Telecom (800 MHz), KT (800 MHz), LG Uplus (800 MHz). Japan: NTT (400 MHz), KDDI (400 MHz), SoftBank (400 MHz), Rakuten (400 MHz). US: overlaps with n261 allocation. The n257 band is the most widely deployed mmWave band globally. (2) n258 (24.25-27.5 GHz): 3.25 GHz total bandwidth. This is the lower part of the mmWave spectrum, providing slightly better propagation than n257 (2-3 dB less path loss). Allocated primarily in European countries. Some coexistence challenges with Earth Exploration Satellite Service (EESS) at 23.8 GHz (the passive sensing band for weather satellites). Power limits may be imposed on the lower edge of n258 to protect EESS. (3) n260 (37-40 GHz): higher frequency means: smaller antenna elements (lambda/2 = 4 mm at 39 GHz, vs 5.4 mm at 28 GHz), allowing more elements per unit area. More path loss (approximately 3 dB more than 28 GHz). More available spectrum in the US (FCC Auction 103 released 3 GHz). Verizon and T-Mobile hold significant n260 spectrum.
Performance Analysis
(1) Subcarrier spacing: FR2 supports 60 kHz and 120 kHz SCS (FR1 uses 15/30/60 kHz). 120 kHz is the dominant choice for FR2 because: larger SCS provides better resilience against phase noise (which is higher at mmWave frequencies). Faster slot timing (125 us slots enable lower latency). Adequate subcarrier count: 400 MHz / 120 kHz = 3333 subcarriers → 264 resource blocks. (2) SSB beam sweeping: the base station transmits synchronization signal blocks (SSBs) in different beam directions. FR2 supports up to 64 SSBs per beam sweep (L_max = 64). The SSB burst operates within a 5 ms window, allowing 64 beams to be swept in 5 ms. Each SSB covers a different angular direction, collectively covering the cell's angular range. The UE measures the received power of each SSB and reports the best beam(s). (3) Slot structure: at 120 kHz SCS: 1 slot = 14 OFDM symbols = 125 us. 8 slots per subframe (1 ms). 80 slots per frame (10 ms). The short slot duration enables rapid beam switching, fast HARQ feedback, and low-latency applications.
- Performance verification: confirm specifications against the application requirements before finalizing the design
- Environmental factors: temperature range, humidity, and vibration affect long-term reliability and parameter drift
- Cost vs. performance: evaluate whether the application demands premium components or standard commercial grades
Design Guidelines
A 5G UE supporting FR2 must implement: (1) Multiple antenna modules (AiP): typically 3-4 modules per phone, each containing 4-8 antenna elements with integrated PA, LNA, and phase shifters. (2) Multi-band support: for global roaming, support n257/n258/n260/n261. The wideband RF front end must cover 24.25-40 GHz (typically with two sub-bands). (3) Beam management: the UE modem implements the 3GPP beam management procedures (P1: initial beam selection, P2: beam refinement, P3: UE beam selection). The UE continuously monitors beam quality and triggers beam failure recovery when the serving beam is lost. (4) Power management: mmWave modules consume 1-3 W each. With 3-4 modules: total power can reach 6-12 W during peak transmission. The phone must manage thermal throttling and duty cycling to prevent overheating.
Frequently Asked Questions
What is the difference between FR1 and FR2?
FR1 (410 MHz - 7.125 GHz): sub-6 GHz. Supports FDD and TDD. SCS: 15/30/60 kHz. Max BW per CC: 100 MHz. Propagation: good (wall penetration, diffraction). Antenna: conventional (4-8 elements, no beamforming required for basic operation). FR2 (24.25 - 52.6 GHz): mmWave. TDD only. SCS: 60/120 kHz. Max BW per CC: 400 MHz. Propagation: poor (LOS required, no wall penetration). Antenna: phased array mandatory (beamforming required for adequate link budget). The key operational impact: FR1 devices are simpler and cheaper (no phased array). FR2 devices add $20-50 in component cost (AiP modules, additional transceiver chains). Most mid-range phones support only FR1; premium phones support both.
How much spectrum does each operator get in FR2?
Allocation varies by country and auction outcome: US (28 GHz, n261): 850 MHz total. Verizon: 300-400 MHz. AT&T: 200-300 MHz. T-Mobile: 200 MHz. US (39 GHz, n260): 3 GHz total. Spread among Verizon, AT&T, T-Mobile, and other holders. Korea (n257): 800 MHz per operator (3 operators = 2.4 GHz used). Japan (n257): 400 MHz per operator (4 operators = 1.6 GHz used). Europe (n258): still being auctioned. Expected 200-800 MHz per operator. Compared to FR1: typical FR1 allocation is 40-100 MHz per operator. FR2 allocations are 3-10× wider, enabling proportionally higher throughput.
Will FR2 spectrum expand further?
3GPP Release 17 extended FR2 to 71 GHz (FR2-2). Future releases are studying: 90-100 GHz for possible 6G allocation. 100-300 GHz (sub-THz) for research-stage 6G. The ITU World Radiocommunication Conference (WRC-2027) will consider additional mmWave/sub-THz allocations. Practically: the 24-40 GHz bands (n257/n258/n260) will remain the primary mmWave bands for the next decade (2025-2035). The 60 GHz band (n263) serves a niche role (short-range, very high throughput). Above 100 GHz: significant technology challenges remain (semiconductor f_T, atmospheric absorption, and packaging).