The Wireless IP Network consists of the following main elements.
It provides 24 ports containing VDSL, synchronization signal and power via two twisted copper pairs. It comes in 19” rack housing and is stackable up to 10 units in one cluster for connection up to 240 base stations. Cable length can be up to 1.5 km. It is installed in combination with VDSL modem equipment.
Ethernet Sync Switch:
It provides 6 ports containing Ethernet, synchronization signal and power over standard CAT-5 cable. Cable length can be up to 100 meters. This sync switch is suitable for outdoor installation. It has a built-in Ethernet switch.
2. IP DECT/WLAN base station
The IP DECT/WLAN base station is primarily designed for outdoor installation. It is equipped with built-in omni-directional antennas as well directional antennas (10dB gain). Additional external high-gain directional antennas can be connected when needed. It has separate DECT and WLAN antenna systems. All antenna system supports space diversity to improve coverage.
From one of the two synchronization units (VDSL or Ethernet) the base station is supplied with:
- IP connection, which can either be VDSL or Ethernet
- Timing synchronizations signal
- 48 volt power
A base station supports up to 11 simultaneous DECT connections and up to 16 WLAN clients. It implements the complete DECT MAC protocol layer and performs audio encoding into IP media streams (over RTP).
It implements full 802.11g independent “FAT” AP functionality including WPA security and network access control.
The same physical IP connection is used for both DECT and WLAN traffic, but two different WLANs are used to provide guaranteed QoS and separate audio streams from WLAN traffic.
Two base station installation scenarios are typically used:
Urban Scenario:involves distributed installation in cells covering the desired area by use of the built-in omni-directional antennas. This can be base stations mounted in for e.g. lamp poles, on buildings in urban areas or indoor installation, etc. This is the traditional microcellular method for achieving high traffic capacity in areas with high population density. The usable range will typically be 300 meters around each base station.
Rural Scenario: involves sector installation on transmission towers and use of the built-in directional antennas. Several base stations are installed at a single location such as a transmission towers or similar. By installing the base stations using built-in directional antennas pointing in different directions, the coverage is divided into sectors so that the usable range is greater, typically up to 800 meters. Repeaters can be installed up to 8km away from the base stations using the Timing Advance feature in the repeater. Up to 6 base stations can be co-located because they automatically select different frequencies and timeslots in order to avoid mutual interference.
