Application Of Wireless LAN Interface In Real-time Voice And Data Over Large Area

As ADSL becomes the best choice of personal Broad Band accesses, more and more carriers select Wireless Broad Band as the best access method of small enterprises. Comparing with DSL, Wireless Broad Band has low cost and could carry more throughputs. It supports voice service and is flexible to be equipped. All these advantages make Wireless Broad Band systems become more acceptable.Wireless Broad Band access started abroad in 1997, the technique can fulfill the needs. But until now did researchers concern about transmitting voice over WLAN(Wireless LAN). Nowadays, most companies could achieve that use Wireless LAN to carry four E1 signals in 10Kms. But few could realize that transmit data and real-time voice, including VoIP(Voice over IP) and E1, over Wireless LAN. We can get from this that our technology, transmit mixed data on Wireless LAN, is advanced.This paper analyzed the detailed characteristics of Wireless LAN and showed the difficulties to use Wireless LAN to transmit voice data, the limited efficient band and unsatisfied Quality of Service guarantee. When data burst, E1 data in the Wireless Broad Band systems will be influenced. In other words, E1 data may be lost in wireless link and this may cause bit errors in E1 signals or even interrupt E1 signals. This paper also proposed an algorithm to transmit both voice and data over Wireless LAN. Except for the basic two modules, QoS(Quality of Service) and state-switching modules, other two extensible modules, compression module and multi-rates module according to the characters of voice data and wireless channel, are given in this paper. These two modules could save broadband and guarantee QoS of voice data.After that, this paper also showed the practical test results in long distance, including E1 and data or VoIP and data, and analyzed the delay parameters of voice data and throughput parameters of data service. At last, some improvements are proposed at the end of the paper.