23 Jan 2012

Successful LTE Active Antenna Field Trial

As part of the deployment of LTE in North America, CommScope has undertaken a multi-site trial for their active antennas.

Rather than using passive antennas that utilise the radiating / receiving elements, CommScope has been using active antennas to enable much higher levels of performance to be achieved.

Working with their partner, Ubidyne, the CommScope active antennas incorporate modular digital circuitry. This attaches directly to individual antenna radiators to enable electronic beam-forming to be achieved thereby increasing the network capacity and performance. This is achieved by integrating the functionality of a traditional remote radio head (RRH) and a dual-polarized antenna into the overall antenna housing for the top of the tower.

The active antenna electronics are distributed within the antenna itself. This means that each antenna element has dedicated transmit and receive paths. This distributed architecture provides the ability to control the amplitude and phase of each radiating element. This is one of the key considerations that enable the feature set of active antenna systems.

With the current global economic climate being what it is, operators are keen to ensure that the new systems they are deploying are able to provide increased return on investment by ensuring efficiency is increased. The use of active antennas could be one route that will enable these expectations to be achieved.

Using new technology such as this, it was necessary to trial the system to ensure that it operated according to expectations. The trials delivered a number of useful results.

• Comparison with passive antennas and remote radio heads. The new system compared well with traditional techniques. This was confirmed by monitoring key performance indicators, including signal-to-noise levels as well as the uplink and downlink throughput rates. The same high performance LTE throughput levels were achievable with an active antenna system.

• Independently tilt of uplink and downlink elevation patterns. This was proved to be very effective, and it was confirmed that this can now allow radio planners to further optimize patterns and increase sector throughput.

• Implementation of vertical sectorization. This demonstrated significant promise for increasing capacity. Essentially, one carrier is dedicated for the inner sector, while a second carrier is dedicated for the outer sector. The results also were in excellent agreement with simulations.

• The self-healing feature of active antennas was implemented and also shows great potential for addressing system availability concerns. By simulating a failure of an individual transceiver path, a new optimized pattern was immediately implemented. Drive tests reinforced that theoretical predictions were accurate.

• Ease of installation of the active antenna system. The installation of the antennas was shown to be able to use all of the same hoisting and installation equipment that they normally would use for a passive antenna. The mounting hardware and grounding kits were identical to what they use for other CommScope products. This would reduce the installation costs and capital outlay as well as reducing training.

• Visual impact. It was seen that once the antennas were mounted on the towers, their appearance blended well with the existing antennas. For cell site owners this is important because the appearance was similar to currently deployed antennas and as a result, their use would not impact leasing costs.

Most popular news in Antennas & propagation