All-Outdoor Microwave Backhaul Solution

Quasi-4G long term evolution (LTE) makes spectrum very flexible and provides ultra-broadband speeds. It is slated to be widely deployed by 2014, but it is difficult to construct mobile backhaul networks that meet the requirements of the LTE era.

Evolution Requirements

LTE has higher peak data rates and better spectrum efficiency than 3G. It also has the distinct advantage of packet-based switching. To accommodate LTE, a mobile backhaul requires

• scalable transmission capacity. A 3G base station transmits at tens of megabits per second, whereas an LTE base station transmits at hundreds of megabits per second. Large-capacity transmission links are necessary for developing microwave equipment for mobile backhaul.
• densely deployed small-cell solution. Traditional macro cellular base stations, which provide wide coverage, cannot meet the explosive demand for data access. Mobile operators have had increasing difficulty acquiring sites for base stations; therefore, small cells have been used in busy areas to extend signal coverage, offload data traffic, and enhance network capacity. Limited coverage and densely deployed small cells are key issues for LTE mobile backhaul.
• smooth evolution with low TCO. Reducing network construction and maintenance costs is always of great concern to operators. To reduce costs, a network can be constructed that meets existing transmission requirements and supports smooth evolution and upgrade. 

Features of Microwave Transmission

Large-capacity transmission, dense coverage by small cells, and low TCO are major requirements of LTE mobile backhaul. To address these requirements, microwave transmission equipment must have the following features:

• Zero-footprint installation

All-outdoor microwave equipment has brand-new system architecture. Traditional split-mount microwave equipment comprises an indoor unit and an outdoor unit. The two units are connected by intermediate frequency cable. The indoor unit is used for baseband modulation, and the outdoor unit is used for receiving and transmitting RF waves. However, all-outdoor microwave equipment integrates these two units into one outdoor unit. An all-in-one integrated design makes the equipment smaller and lighter so that the unit can be mounted on an antenna pole. An all-outdoor, zero-footprint installation makes site rental unnecessary and is an ideal backhaul solution for small cells in the LTE era.

• Outstanding system functionalities

All mainstream microwave equipment supports 256-QAM. Higher-order modulation and demodulation schemes, such as 512-QAM or 1024-QAM, can be used to greatly improve spectrum efficiency and meet the fast-growing need for capacity in LTE mobile backhaul. Highly reliable link transmission is also necessary for microwave transmission equipment. Diverse protection modes, such as hot standby protection, space diversity, and frequency diversity, and switching within 50 ms can make link transmission more reliable.

• Excellent user experience

Optimal design makes microwave equipment small and light so that engineers can carry it up towers with one hand. This alleviates difficulties during construction and installation. Advanced power-over-Ethernet technology is also used to reduce cabling between devices, reduce construction costs, and accelerate deployment. Complete performance statistics and an integrated network element management system help staff carry out remote maintenance in the background and lighten their workloads.

• Universal equipment platform

In mobile backhaul, there are access, relay and convergence scenarios, and each scenario has different transmission requirements. Therefore, it is very important to provide a universal equipment platform that can cover all application scenarios. This platform can greatly reduce the number of spare parts, equipment maintenance cost, and the difficulty of performing maintenance.

• Low TCO

Optimizing hardware cost and system power consumption can reduce capex and opex. This protects an operator's investment.

ZTE's All-Outdoor Microwave Backhaul Solution

ZTE has developed an all-outdoor microwave backhaul solution with ZXMW NR8950 as its core. ZXMW NR8950 has a complete set of functions and supports smooth evolution from 2G to LTE.

ZXMW NR8950 uses highly integrated all-outdoor system architecture that can cover all application scenarios. It is a low-cost, all-outdoor, zero-footprint access solution at the end node and allows for multidirectional transmission convergence at the convergence node. Low power consumption and low TCO are the biggest highlights of the all-outdoor system architecture.

ZXMW NR8950 supports 1024-QAM, the highest-order modulation in the industry. Compared with mainstream 256-QAM, 1024-QAM can increase transmission capacity by 25 percent. This improves spectrum efficiency and saves bandwidth. With advanced multilayer Ethernet header compression, physical layer link aggregation, and cross-polarization interference cancellation technologies, ZXMW NR8950 enables a single carrier to reach a transmission bandwidth of 2 Gbps. ZXMW NR8950 also transmits at high power to increase system gain and transmission distance of the link. High-order modulation and high transmitting power improve equipment performance and satisfy the transmission requirements of LTE mobile backhaul.

Operators seek to improve spectrum efficiency and reduce costs through smooth migration and reducing the footprint. To this end, ZTE's all-outdoor microwave backhaul solution is invaluable.