MESH Wireless PCM Information Transmission Access Equipment
The wireless PCM integrates PCM technology, PDH technology, pseudo-wire emulation technology, and wireless bridge technology, serving as a highly integrated, all-in-one access device that enables users to enjoy high-performance traditional PCM interfaces while rapidly establishing transmission links.
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Keywords: MESH Wireless PCM, Wireless PDH, Wireless PCM, Wireless E1 Transmission, Wireless Integrated Service Transmission, Microwave E1 Transmission, Microwave Multiplexing Equipment
Overview
In the construction and operation & maintenance of airport information communication systems, it is common to encounter new or temporary information points without fiber-optic cabling, locations unsuitable for fiber deployment, or situations where existing fiber has been damaged. In such cases, a wireless PDH transmission system becomes essential.
PDH and SDH transmission equipment offer advantages such as constant transmission delay, stable bandwidth, exclusive bandwidth for user terminals, excellent signal quality, and strong confidentiality—features that make them irreplaceable for IP-based terminal services.
PDH and SDH systems support both fiber-optic and wireless transmission modes, providing clock synchronization or pseudo-synchronization transmission. Optical terminals are widely used, while wireless SDH typically operates at frequencies above 10 GHz, resulting in high equipment costs. Wireless PDH, although also using different uplink and downlink frequency points, is less convenient to deploy and has limited application. However, a newer technology—pseudo-wire emulation over IP—can now transmit E1 signals, enabling compatibility with traditional PCM terminals. This technology allows conventional E1 access to be carried over wireless bridges, leveraging the vast market advantages of wireless bridges to ensure high-quality service for legacy PCM terminals, while achieving the transmission performance of wireless PDH.
The wireless bridge market is extensive, with high-quality, cost-effective products available. These devices can operate across a wide frequency range, enabling avoidance of interference with airport facilities. Given their high-frequency operation and generally good line-of-sight conditions at airports, directional antennas can be used to enhance transmission performance and interference resistance.
Wireless bridges support point-to-point, point-to-multipoint, and MESH relay transmission modes, offering flexible deployment. With improved frequency customization technology, they can operate on ideal frequency channels, effectively mitigating environmental interference.
The IDM series from Raytrans provides an integrated wireless PDH + PCM information access and transmission solution. It combines the ease of deployment of wireless network products with a wide range of PCM service access interfaces, including FXO/FXS, EM audio two- and four-wire, synchronous/asynchronous serial data interfaces (RS232/RS422/RS485/RS429/V.35), and video interfaces.
Wireless PCM Equipment Application
Wireless PCM Technical Principles
Wireless PCM Technical Specifications
The wireless PCM integrates PCM technology, PDH technology, pseudo-wire emulation technology, and wireless bridge technology, serving as a highly integrated, all-in-one access device that enables users to enjoy high-performance traditional PCM interfaces while rapidly establishing transmission links.
4.1 Wireless Transmission Specifications
- Operates in the 4920
6100 MHz frequency band; RF MIMO adopts a 2T2R architecture; wireless bandwidth supports 5/10/20/40 MHz configuration; physical layer bandwidth of 300 Mbps; maximum transmit power of 400 mW; receive sensitivity as high as -96 dBm; built-in 18 dBi directional dual-polarized antenna; recommended bridge distance of 15 km. - Supports TDMA protocol and TDMA bandwidth allocation function, effectively improving bandwidth utilization in PTMP mode.
- Supports Dynamic Frequency Selection (DFS).
- Supports automatic transmit power adjustment (IEEE 802.11h); manual adjustment step size of 1 dBm.
- Supports uplink/downlink bandwidth allocation, client isolation, bandwidth control, and client signal strength-based access control.
- Supports IP68 waterproof rating; operates within -40~75°C temperature range.
4.2 E1 Line Specifications
- Supports jitter compensation for packet delay variation from 1.5 ms to 125 ms.
- Clock accuracy up to 16 ppb, meeting 3G base station clock accuracy requirements, effectively ensuring data backhaul.
- Multiple clock modes available: internal clock, user clock, recovered clock, and external clock.
- Low data transmission delay, minimal signal jitter and drift, ensuring TDM service quality.
- Features comprehensive LED alarm indicators for easy fault localization.
- Excellent IP network transmission performance.
- Configurable packet buffer space, enabling end-to-end E1 delay of less than 1 ms.
- Adjustable bandwidth function: E1 interface count can be adjusted based on the number of E1s or the available bandwidth on the IP network.
- Configurable packet size to balance PSN throughput and latency, delivering excellent performance on Layer 2 Ethernet switches.
E1 interface line rate | 2048Kbps ±50ppm | Supported number | 8 |
Standard protocol | Supports ITU-T G.703 /G.706/G.704 | Line code | AMI/HDB3 |
Physical interface | RJ45 (balanced) / BNC (unbalanced) | Jitter characteristics | ITU-T G.823 |
Impedance | 75Ω (unbalanced) / 120Ω (balanced) | Clock recovery accuracy | 100ppm / 16ppb |
E1 interface configurable | E1 interface supports local or remote configuration via software | ||
4.3 PCM Interface Specifications
4.3.1 FXO, FXS
Compression rate | ITU G.711 A-law | Audio range | 300Hz~3400Hz |
Input/Output impedance | 200Ω+560Ω//0.1μF | Loop current | 25mA / circuit |
4.3.2 EM 2/4-wire
Compression rate |
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