Understanding frequency bands and propagation characteristics
Radio frequency spectrum is a finite natural resource essential for wireless communications. Cellular networks operate in licensed frequency bands allocated by regulatory authorities to ensure interference-free operation.
Different frequency bands exhibit distinct propagation characteristics. Lower frequencies provide better coverage and building penetration, while higher frequencies offer greater bandwidth and capacity.
Spectrum efficiency measures how effectively networks utilize available frequencies. Advanced technologies like OFDMA, MIMO, and carrier aggregation maximize spectral efficiency.
Uplink: 824-849 MHz | Downlink: 869-894 MHz
Used in: Americas, Asia-PacificUplink: 880-915 MHz | Downlink: 925-960 MHz
Used in: Europe, Asia, Middle EastUplink: 832-862 MHz | Downlink: 791-821 MHz
Used in: Europe (Digital Dividend)Uplink: 1710-1785 MHz | Downlink: 1805-1880 MHz
Used in: Worldwide (most common)Uplink: 2500-2570 MHz | Downlink: 2620-2690 MHz
Used in: Europe, Asia, Latin AmericaTDD: 2496-2690 MHz
Used in: Worldwide for 4G/5GTDD: 3300-3800 MHz
Used in: Global 5G deploymentTDD: 3300-4200 MHz
Used in: 5G C-bandTDD: 26500-29500 MHz
Used in: 5G mmWave (Americas, Asia)TDD: 24250-27500 MHz
Used in: 5G mmWave (Europe)Signal strength decreases with distance from transmitter. Path loss increases with frequency and is affected by obstacles, terrain, and atmospheric conditions.
Large obstacles like buildings and hills cause signal attenuation. Shadow fading varies slowly as mobile device moves through environment.
Signals reflect off surfaces creating multiple paths to receiver. Constructive and destructive interference causes rapid signal fluctuations.
Relative motion between transmitter and receiver causes frequency shift. Higher speeds increase Doppler spread affecting channel estimation.
Radio waves bend around obstacles enabling non-line-of-sight communication. More pronounced at lower frequencies with longer wavelengths.
Building materials attenuate signals. Concrete and metal cause significant loss. Higher frequencies experience greater penetration loss.
Separate frequency bands for uplink and downlink transmission. Simultaneous bidirectional communication with paired spectrum. Common in 2G, 3G, and 4G networks.
Single frequency band shared between uplink and downlink using time slots. Flexible allocation adapts to traffic asymmetry. Preferred for 5G deployment with unpaired spectrum.
Multiple technologies (4G/5G) share same frequency band dynamically. Enables gradual 5G deployment without requiring dedicated spectrum. Resource allocation adjusts in real-time.
Combines multiple frequency bands to increase bandwidth and data rates. Essential technology for LTE-Advanced and 5G networks.
Multiple adjacent carriers within same frequency band. Simplest implementation with minimal complexity.
Non-adjacent carriers within same band. Enables use of fragmented spectrum holdings.
Carriers from different frequency bands. Combines coverage and capacity benefits of multiple bands.
Same frequencies used in non-adjacent cells to minimize co-channel interference. Reuse factor determines spectral efficiency versus interference trade-off.
Adjusts transmission power to maintain signal quality while minimizing interference to neighboring cells. Essential for uplink interference management.
Directional antennas focus signals toward intended users. Reduces interference and improves signal quality. Critical for 5G massive MIMO systems.
Base stations coordinate resource allocation to avoid interference. Frequency domain and time domain techniques protect cell-edge users.
Multiple base stations jointly transmit to or receive from user equipment. Turns interference into useful signal through coordination.
Advanced receivers detect and subtract interfering signals. Successive interference cancellation improves capacity in dense deployments.
Spectral efficiency measures data throughput per unit bandwidth. Higher efficiency enables more capacity from limited spectrum resources.
