Transcript Document
Wireless communication in the areas of difficult propagation conditions Krzysztof Wierny AFCEA's International Student Conference "Students at Work!" Radiotechnika Marketing LTD. Military University of Technology STORCZYK Communication System AT AK AT AK AT AK COTS technology Military applications 1. System EXDWN from Xacta 2.System (USA) Battle LAN S-WiFi from Thales •Portable accessMeshCom point or bridge 3.System TELCOR •Access point or b, bridge for using on the •IEEE 802.11 g, 54Mb/s, from Telefunken vehicles 2.4GHz •Access point or bridge •IEEE802.11b,g; 2-6 •Omni andb,g; directional antennas •IEEE 802.11 2,4GHz, Ghz; •Output power 1W300-1500m both on the mast •(1-10GHz ),range •Range 1 km in open area (11Mb/s) •security WPA-TKIP,EAP MAC COTS technology Military applications Radiotechnika Marketing LTD. WLANBOX-Bridge 1-2,4 military communication systems requirements • short deploying time and establishing communication, • precluding easy localization and detection of communication node • transmission range big enough to enable dispersion of shelters in the large area • operation in military frequency bands. Commercial communications wireless systems: ADVANTAGES: • provides wide range available bit rates from 1 Mbit/s to 54 Mbit/s, • provides greater flexibility in network construction, • enables transfer modern data transmission technologies and security mechanisms on military area . DISADVANTAGES: • WLAN have insufficient communication range • operating in commercially available, unlicensed frequency bands, crowd of users • restricted transmitters power, • need precise positioning of directional aerials in bridge connections WLANBOX-Bridge operational parameters • output power 4W • bandwidth converter from 2,4Ghz to 1,6Ghz • system is placed in small portable box • operation up to 5 hours from the battery • connection with communication shelters through the PKS and PKŚ cables • optical indicators of signal level for easy alignment antennas System on measuring position WLANBOX-Bridge • 2 pcs of WLANBOX-BRIDGE 1-2.4 modules • 2 omnidirectional antennas 12dBi on frequency band 2,4 GHz • 2 directional antennas 24dBi on frequency band 2,4 GHz • 2 tripad folding masts at 4m high • 6m long antennas feed coaxial cables • 2 pcs.of military notebooks with Pentium M processor. Measurements - variable parameters • Signal Strength • Reliability of data transfers during transmission of 10 Mbytes long files. • Error rate • average effective data rate. Measurements result Antenna type freq./output power Directional 1,6GHz, 4W Directional 2,4GHz, 30mW Omnidirectional 2,4GHz, 30mW max. distance between antennas 800m 220m 130m transfer rate 500kb/s 300kb/s 250kb/s error rate 10% 12% 16% signal strength 22% 18% 18% reliability Rarely interrupted often interrupted transfer often interrupted transfer distance between antennas 600m 150m ~100m transfer rate 2Mb/s 1Mb/s 1Mb/s error rate 1% 3% 3% signal strength 42% 40% 40% reliability Stable transfer Stable transfer Stable transfer Conclusions • Propagation of waves in microwave bands in forests limited because of strong suppression caused by branches, leaves and trunks of trees • Range of omnidirectional antennas is insufficient in dense forests area and can used with satisfaction for military application only at distance up to 100m. • Using of amplifier with 4W output power brought in an increase of signal range of about four times • Duration of antennas positioning is much longer for directional antennas than omnidirectional Implementation of wireless WLANBOX Bridge system for military application. 1.wireless bridge can improve connecting remote command post (placed in building, tent) with communication shelter. Implementation……cd 2. Connection between vehicles in motion Implementation…… 3. Communication on difficult area Thank you very much for your attention