Solutions
Due to the shielding effect of the shielding box inside of the building and the complex structure, indoor mobile transmission tends to fail. The higher space of buildings is subject to wireless frequency interference and thus there would be mobile signal instability. Voice connection quality is difficult to guarantee. In large shopping malls, conference centers and other large buildings, local network capacity cannot meet users’ needs because of the overcrowded mobile station usage. These problems can be effectively solved by the indoor distribution coverage. This system could provide indoor users with a good and clear voice connection quality.
A reasonably-designed indoor distribution system, which accepts signals from macrocells or microcells, would effectively amplify the signals required by the repeater, and distribute the signals evenly with indoor wireless distribution systems, realizing the optimization of indoor wireless network and providing users with a good wireless communication environment. Less antennas and lower power distribution system is applied in indoor weak and blind areas, focusing on satisfying coverage needs. Multiple antennas and normal power is applied in high mobile communication traffic type indoor environment. The key point is to fully absorb the traffic and share load of outdoor base stations. Multiple antennas and higher power distribution is applied in indoor environment suffering from interference, focusing on providing main control signals and blinding interference.
Tunnels commonly exist along roads and railways, sometimes in large-scale hydropower projects. Due to their narrow, closed structure, tunnels have become typical areas in network planning. The completion of tunnel coverage is one key step in improving brand reputation and increasing overall competitiveness to an operator.
Flexible and economical methods could be adopted in cases of tunnel coverage. Short tunnels can be constructed by installing high-power outdoor repeaters near the tunnel entrance, using high-gain plate-shaped directional antennas, or installing directional antennas as radio frequency distribution. Long tunnels can be constructed by laying leaky cables.
Due to geographical location, the coverage distance of the coastal base station is limited to inshore areas. It affects the quality of mobile communication of sea-surface users, resulting in the loss of users. The realization of offshore coverage is an important step to enhance reputation and expand user volume.
Base station amplifier or tower amplifier would cooperate with base station by using extension system to enhance signal strength, and simultaneously adjust the dual-slot parameters to expand the offshore coverage. Also it could adopt outdoor repeater coverage mode. With large output power, it can provide better coverage for offshore waters.
Due to the multiple services of 3G, about 60%-70% of communication in the 3G era occur indoors. The existing 2G system needs to be upgraded to meet 3G requirements. Preparing for 3G indoor distribution system upgrading to fully provide continuous and stable communication and data services to improve the user's sense of identity and satisfaction with 3G, and enhance the overall performance of the wireless network, which also meet the operator’s need to strategic development.
Different coverage methods are adopted according to the different needs of high, middle and low-end users. Areas of high data traffic are covered by hot spots when continuous coverage is guaranteed. The entire system uses broadband devices and antennas compatible with 3G frequency bands. Low-loss transmission feeders is used to make the most of existing 2G distribution system, minimizing the difficulty of upgrading and providing stable communication services.
Because of the obstruction of mountains，it is not easy for roads and railways to complete continuous coverage only by base stations. Coverage breakpoints would exist, especially in hills. This existence causes inconvenience and thus affects the operator's brand image. Completing the continuous coverage of roads and railways is very important for maintaining the reputation and image of operators.
In the blind spot areas of roads and railways, it is difficult to set up base stations due to high cost and varied topography. To achieve full coverage, easily installed high-power outdoor repeater which costs less could be applied in this situation. The choice of omnidirectional antenna or directional antenna depends on the circumstances. The downtilt of antenna should be paid more attention to, to prevent cross-region coverage causing interference. The equipment could take power from nearby villages and utilize solar power when nearby power is unavailable.
In remote areas such as the suburbs and rural areas, the signal becomes weak or the place is a blind spot due to the limited transmission distance of base station and complex geographical environment. Building a new base station would not only cost long construction time, but also much money. Also, because of low utilization rate of base station system, it will cause great waste and increased operating cost by pursuing quantity of base stations. In this situation, repeater system shows its increasing advantages.
According to wireless network conditions, broadband repeaters with low cost can be used in areas where base stations are of small quantity and signal source is relatively clean. For areas with complex wireless networks, frequency selective direct amplification with extremely strong frequency selection capability could be used. For those areas where isolation is difficult and at the same time signal source base station is visible, frequency-shifting repeaters without self-excitation could be used. Optical fiber repeaters could be used in areas where it is difficult to obtain a signal source. When repeaters are set up at the right place, excellent coverage could be achieved by using high-gain antennas. Thus better network optimization with less investment and shorter construction period could be achieved.