Testbed Deployment
Base station and Antenna
NITOS has been enhanced by means of the Airspan Air4G-WL24G operating on the 2.53-2.63GHz bands. The main features of the BS are summarized as follows:
- It implements the IEEE 802.16e standard, introduced initially in 2005, which is based on the SOFDMA technology.
- It consists of a single outdoor unit, thus reducing operation expenses.
- It supports up to 40dBm transmission power, with dual radios and four receivers, thus supporting 2x4 MIMO connectivity.
- Channel bandwidth can be selected from the following configurations: 3.5MHz, 5MHz, 7MHz, 10MHz and can be configured to use 2x7MHz or 2x10MHz channels.
- It supports standalone mode without the need of purchasing an extra ASN Gateway.
- The management and data paths to and from the base station can be configured using VLANs
- Supports Gigabit Ethernet connectivity, using either copper or fiber cabling.
Its most remarkable feature that enables its integration in an experimental testbed environment is the capability of it to operate in a standalone mode, with or without user authentication, and without the need to purchase an ASN GW in order to operate it. Its overall consumption depends on its configuration, and indicatively each 2x10W base station sector draws 200W of power.
The antenna acquired for its operation is an AW3008 sector antenna with CL-V-104 mounting kit from Alpha Wireless Ltd.
Antenna 's specifications are detailed in the following table.
|
Frequency Range: |
2300 - 2700MHz |
|
Gain: |
17 dBi |
|
Return Loss: |
>14dB |
|
Power Handling: |
150W |
|
Impedance |
50 Ohm |
|
Connector Type |
4 x N Type Female |
|
Weight |
9kg |
|
Dimensions (LxWxD) |
1050 x 260 x 85mm |
Even though operation in the 2.X Ghz bands has a maximum consumption of 370 Watts, requiring an input voltage of -48V DC, NITlab selected to use a MEAN-WELL power supply supporting load of up to 480 Watt. DC power cable (shipped with the Airspan BS), is an unearthed DC cable and is approximately 75 feet long, which meets NITOS’ needs.
As the initial configuration took place in the offices of UTH, the signal that the BS was transmitting had to be reduced. Therefore, NITlab intercepted the BS to antenna connection by mounting attenuators, able to provide 30 dbm at 50 Watt signal attenuation. To this end the 50FHXC-030-50 N RF attenuator from JFW industries was used. In the following figure the Air4G-WL24G Base Station with the attenuators installed is illustrated.
Since the BS acquired is supporting Time Division Duplex (TDD) multiplexing, a GPS module is required for proper timing of the timing slots during which each Subscribed Station (SS) can transmit. The GPS antenna shipped with the BS unit was not working properly and therefore deferred more the process of its deployment. NITlab is currently in the process of replacing the faulty antenna, and have managed to operate the BS by using a 3rd party GPS antenna (RoHS COMPLIANT Model: GPS 001 Voltage: 3~5v frequency: 1575.42 MHz). A lighting surge protector which is shipped is attached on the GPS connector, and the replacement antenna is attached on it by using a RG58 cable.
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