System Overview
The digital fiber repeater system consists of local optical units (LOUs) and remote optical units (ROUs). Developed to address difficult base station siting, high equipment room investment and low resource utilization, it converts RF into digital signals for optical transmission. Digital compensation for optical loss between LOU and ROU improves system efficiency.
Flexible network configurations and centralized equipment rooms address the cost and siting challenges of new or relocated base stations. High-traffic sites can use new or expanded sectors as sources, while lower-traffic sites or traffic resource scheduling applications can share sectors. Cascaded networking also reduces investment in fiber resources.
Remote monitoring and alarms simplify supervision, adjustment and maintenance. If external AC power fails, the system can continue sending alarms to the monitoring center for one hour, providing an economical solution for expanding mobile coverage.
A fully modular design allows LOUs and ROUs to be combined as required by each project, providing operators with cost-effective network optimization and coverage.
Technical Features
Integrated RF, digital processing and CPU control for stable and reliable performance
Digital or analog predistortion provides excellent linearity
Devices support mutual management and debugging, with access to the entire network from any node
Local management through serial and Ethernet interfaces
Built-in efficient regulated power supply with multiple supply options
Digital processing provides stable signal quality, higher transmission rates and greater capacity
Standard optical/electrical interfaces and digital optical transmission address optical path attenuation
High-speed, wide-dynamic-range ADC/DAC technology preserves signal quality
Digital predistortion ensures output linearity
Doherty power amplifier architecture improves system efficiency
Multiple network configurations simplify project deployment
Compact standard 19-inch 1U near-end enclosure
Main RF Specifications
Test Item | Forward Link | Reverse Link 1 | |
Frequency Range | 2110-2165MHz | 1920-1975MHz | |
Nominal Maximum Output Power | 48dBm | 0/-5dBm | |
Automatic Level Control (ALC) | At maximum power, an input increase up to 10 dB must keep output variation within ±2 dB. Above a 10 dB input increase, output variation must remain within ±2 dB or the unit must shut down. | ||
Maximum Gain | 52dB±2dB | ||
Gain Adjustment Range | ≥30 dB; gain adjustment step ≤1 dB | ||
Gain Adjustment Error | Total error ≤±1 dB within 0-10 dB | ||
Total error ≤±1 dB within 10-20 dB | |||
Total error ≤±1.5 dB above 20 dB | |||
In-band Ripple | ≤3 dB peak-to-peak | ||
Noise Figure | -- | ≤5.0dB | |
Frequency Error | ≤±0.01ppm | ||
Transmission Delay | ≤10μs | ||
Input/Output VSWR | ≤1.5 | ||
Error Vector Magnitude (EVM) | ≤3.5%(256QAM) | ||
ACLR | ≤-45dBc | ||
System Efficiency | >15% | ||
Optical Performance Requirements | Optical output power: ≥-9 dBm Optical receiver sensitivity: ≤-24 dBm (BER = 10^-12) Optical dynamic range: ≥15 dB; near-end to remote distance ≥20 km, assessed by waveform quality factor | ||
Network Topology | Supports at least six-stage cascaded networks, four-port star networks and hybrid configurations Ring protection supported | ||
Delay Adjustment | After adjustment, delays from the relay unit to each connected remote unit are similar, with a difference of <1 µs between remote units | ||
Backup Switching (Optional) | If the primary relay unit reports power loss, a power module fault or another manufacturer-defined alarm, RF and optical links can automatically switch to a backup relay unit while maintaining the remote connection. | ||
Optical Bypass (Optional) | If the primary relay unit reports power loss, the optical link can automatically switch to the next remote unit in the cascade to maintain connectivity. | ||
