Low-Cost Power Solution for Co-Siting Base Stations

The Indian telecom market has prospered in recent years and operators, eager to capture a share, have been rapidly building networks. However, infrastructure in India is backward, and construction of equipment rooms, iron towers, diesel generators, and power systems has stymied network deployment. To overcome this, operators have set up companies specializing in infrastructure construction and maintenance. Among them are Indus Towers (a joint venture of Vodafone, Barti, and Idea), QUIPPO (with investment from TaTa), and American Towers (100% U.S. owned). These companies construct network related infrastructure and then rent it out to operators. Such a business model helps accelerate network deployment and lower CAPEX. But some things require consideration in power system design:

■    Power must be supplied to equipment of multiple operators. A conventional base station power system only supplies power to a single operator, so its output capacity is limited. Indus Towers supplies power to four operators, so the power system must take into account radio and transmission equipment of each operator, and more than 16 outputs must be provided for power distribution;

■    An infrastructure company that rents a power system must individually meter and charge each operator according to electricity consumption;

■    OPEX of an infrastructure company is mostly due to electrical consumption of on-site power systems. Therefore, a highly efficient power system is required to cut the company’s OPEX.

After surveying the market for nearly half a year and consulting its customers, ZTE launched the ZXDU68 T451 low-cost power solution for co-siting base stations. Characteristics of Indian infrastructure companies and markets were taken into account to deliver the highest benefits to customers.

Full satisfaction of site requirements

ZXDU68 T451 has a capacity of 24kW in its full configuration, more than twice that of a conventional base station power system. It can supply power simultaneously to base stations of four operators.

ZXDU68 T451 supports up to 18 outputs, 16 of which can be divided into four groups to distribute power to base stations of different operators. Each group includes three outputs for low voltage disconnection 1 (LVD1) and one output for LVD2. Two 250A battery fuses are configured for connection of large-capacity batteries.

To protect equipment connected to the power system, class D surge protection devices are installed on the DC output side of ZXDU68 T451. These are designed to discharge lightning that may be attracted to the aviation lights on the tower.

ZXDU68 T451 provides up to eight potential free contactor outputs for real-time reporting of power state to other equipment.

Best assured customer benefits

■    High efficiency: Efficiency is key in reducing OPEX. ZXDU68 T451 adopts a high-efficiency power converter module that increases power efficiency up to 95%. To further reduce power loss, ZXDU68 T451 has dynamic power management. When the load is light, surplus modules are dormant for high efficiency;

■    Easy charging: To aid in charging different operators, ZXDU68 T451 allows DC-based charging. Its embedded energy meter can display electricity use of four operators. The meter readings can be reset to 0 but no modification by external interface is allowed. Thus, a reliable charging reference is provided. The energy meter also supports RS232 communications. With a suitable network connection, the infrastructure company can read the meter remotely; 

■    Compact installation: Because one site must accommodate equipment of four operators, room space is very limited. To save space, ZXDU68 T451 is only 600mm high. It has a specially designed bracket so the power system can be mounted directly over the battery shelf;

■    Low cost: Reducing infrastructure CAPEX is an ongoing concern. ZXDU68 T451 is designed with universal modules, uniquely packaged together. Good balance is achieved between functionality and cost, and all customer requirements are met. 

With accurate market positioning, excellent performance, and reliable quality, ZXDU68 T451 power solution for co-siting base stations has been enthusiastically received. 

ZXDU68 T451 was chosen by Indus Towers for its group purchase in October 2009. After assessing sites with ZXDU68 T451, Indus Towers concluded their TCO would be reduced by more than 30%. In addition to 1000 power units shipped in December 2009, Indus Towers will order more to be shipped in 2010.

In March 2010, Vodafone Essar in India chose ZXDU68 T451 for its group purchase after comprehensively analyzing technical indexes, cost, and maintainability.

The power sharing business model in India allows for reduced CAPEX and OPEX, and fast deployment. It is especially suitable for construction of telecommunications networks in emerging markets. As 3G networks are rolled out in countries such as India, Vietnam, and Indonesia, this business model will become widely accepted. ZTE’s ZXDU68 T451 is well positioned to capitalize on the trend towards power sharing for co-siting base stations.