While the present nature of DAS (Distributed Antenna Systems), in healthcare and other vertical markets; the (DAS) is becoming the defacto wireless medium present. This has become the outcome of the convergence and/or non -convergence of WLAN with a DAS that is also becoming a reality today going forward ore for wireless communications at large. DAS systems were desinged to transmit frequencies such as 850MHz, 1900MHz, and also 800MHz. At the time, there was also a requirement for for UHF and now pending AWS frequencies to also the extent public safety at 700MHz. Typical link budget requirements required signal strength -85dBm. As early stage WLAN(s), at 2.4GHz (802.11b/g), they also demanded a signal strength of -65dBm for voice over IP. However this all changed with 802.11a, at 5.0GHz. Infrastructure to overcome this frequency became and is a huge hurdle due to the link budget. Not only the technical, but the financial. Now with the advent of 802.11n and requirements for MIMO, every enterrprise wireless environment needs to look at the cost and technical considerations of a converged or non converged model. At the end of the day, it probably makes a lot of sense to separate the WLAN model from the cellular and/or PCS/AWS/Public Safety model.
