Vivato Based VoIP Application: Wi-Fi Base Station roduction 82. (Wi-Fi) wireless local area networks (WLANs) have enjoyed enormous growth over the last few years. With that growth Wi-Fi has expanded into standard voice communications through the use of VoIP (Voice over ernet Protocol). The introduction of a wireless component adds the additional complications of coverage, coverage quality, wireless network capacity and interference control to the already difficult task of supporting quality voice services using a communications network optimized for data services. The Vivato adaptive beam forming technology provides several unique solutions to these problems. Open Platform A major benefit to the Vivato Wi-Fi system is that it can easily integrate into existing networks, either wired or wireless. All of the Vivato smart antennae based products use standardized / Ethernet and TCP/IP protocols and can communicated easily to other standardized network equipment. This allows fast and inexpensive setup and avoids having to use proprietary equipment. The Vivato Wi-Fi products communicate to any standard 82. PDA, laptop, VoIP handset or handheld client device. This means that any off-theshelf Wi-Fi devices will be able to communicate to the wireless network with out modification or specialized software, and no expensive proprietary equipment is required. Scalable The Vivato Wi-Fi system can grow and expand on an as-needed basis. The design and architecture allows for single or multiple products to be added when extra bandwidth or coverage is required. This pay-as-you-grow design allows customers to minimize their investment and only purchase what they need. Wireless LAN Components As shown in Figure, the simplified network would consist of wireless equipment added to a standard data communications network. Typical Wi-Fi equipment is limited to a range of 2 to 3 feet between standard access points (APs) using omni-directional antennas and laptop clients in an open environment. This range amounts to a circular coverage area of approximately one hundredth of a square mile. High-gain omni antennas can be added to increase range and coverage at the expense of lower throughput due to increased levels of received interference []. A high-gain sectored antenna can be added to spatially reduce
hp proliant DL36g3 hp proliant DL36g3 hp proliant DL36g3 Lan Lan Lan the effect of interference, but this configuration suffers from decreased coverage area due to the smaller inherent field of view of these devices. Wi-Fi Outdoor Base Station Up to 9 feet ernet o Up to 6 miles 2 o Up to 2.6 miles Wi-Fi AP/Bridge Enterprise Servers Figure : Long Range High Coverage Wi-Fi Vivato, Smart Antennae based, Wi-Fi base stations combine the long range and interference rejection of a high-gain antenna and the coverage advantage of wide field-of-view omni systems by electronically synthesizing many individually-pointed, high-gain antennas. As a result, a single base station mounted on a 6 foot mast can cover an area of nominally 5 square miles for outdoor hand held Wi-Fi clients. Unlike conventional Wi-Fi equipment, multiple base stations can be located on the same mast to increase this coverage. The expanded coverage capability from a single location greatly reduces both time to deploy and overall cost of the wireless network. Wi-Fi APs/bridges or microcells can be added where needed to provide additional connectivity to clients that are out of direct range due to distance, shadow fading, or building wall attenuation. The microcell can be configured with high-gain antennas to increase the range of both the Wireless Distribution System (WDS) backhaul links and links to client devices. The network designer will typically need to add only a few microcells to a network, thus minimizing the total number of wireless devices and associated management, needed for full coverage. This Macro cell / Micro cell network configuration has the advantage of limiting the number of wireless backhaul links which introduce unwanted latency and jitter which adversely affects applications such as Wireless VoIP. Limiting the use of meshing (dynamic in band back haul) increases the network capacity available to customers maximizing the number of customers that can be supported by each base station. Both of these design concepts in conjunction with the Vivato smart antenna ability to reject interference allow the deployment of high quality robust wireless systems that successfully operate with other users in the band. Wireless System Design A typical Wi-Fi access point (AP) mesh solution is shown below. Many pico-cellular hot spots are used to cover the deployment. Even for a small coverage area of 5,
residents, this ordinary AP approach would require hundreds of APs. Each AP would require a professional installation on a tall structure. Each AP in this picocellular deployment would also require power and some sort of network connectivity or back-haul. This is often accomplished using various Mesh techniques where user traffic and back haul traffic are daisy chained through the network until a connection to the wired network can be made. Consider the maintenance challenge with hundreds of APs and potentially hundreds of points-of-failure. Picocellular architectures require long installation times and can be extremely expensive to deploy with the hardware, professional services and the recurring operating expenditures. There are many dependencies on the overall Wi-Fi deployment size of coverage area, building height, building material and wall thickness, terrain and other obstacles such as large trees. Vivato Base Station and AP Coverage Increased coverage due to the use of Vivato Wi-Fi Base Stations can drastically reduce the overall equipment needed. The same city deployment is shown with a Vivato Base Station and a Vivato AP/Bridge to fill an area not covered by the base station. This meshed combination of extended range Base Stations and AP/Bridges keeps the complexity low, while giving the city the largest and most efficient wireless coverage at the lowest net cost. Mobility is an important consideration in a system intended to support VoIP. As a user moves through the network the VoIP equipment must select new sites as the coverage from one site becomes insufficient to support a connection. In a small cell system coverage varies rapidly and new cells must be found at a near continuous rate. A network designed with larger cells requires fewer handoffs between cells resulting in higher call quality and reliability. Vivato VoIP Experience The VoIP market continues to experience incredible growth, development of new products, improvements in capacity and improvements in quality. Vivato has performed interoperability, quality and capacity tests using Spectralink, Net2Phone and Vocera handsets. Additionally
Vivato has implemented the Spectralink voice QOS system (SVP) which adds a first layer of voice priority to Vivato base stations. Figure 2: Downtown Spokane test bed. Handsets were evaluated in the Spokane WiFi test bed shown in figure 2. This system consists of five Vivato base stations and 2 Vivato micro cells in a configuration typical for an urban deployment. Each handset exhibits a unique set of characteristics reflecting the intent of the vendor in maximizing quality, capacity, value, look and feel, mobility, etc. In all cases Vivato equipment has been found to have superior coverage and superior interference tolerance compared to standard AP based solutions. These informal tests have shown that Vivato supports both voice quality and capacity as predicted by the handset vendor. Both quality and capacity are variable dependent on the specific design tradeoffs of the handset. It is interesting to note that these goals could be met in an active urban environment with equipment intended for use in a controlled enterprise environment. This is largely a consequence of the rejection of other AP interference by the Vivato smart antenna system. In this rapidly developing area Vivato intends to continue to work with customers and vendors to maintain and optimize Vivato systems for voice applications. Vivato has unique internal expertise for the systems aspects of supporting VoIP developed through decades of experience with developing and deploying cellular wireless voice and IP networks. As 82.6 reaches deployable status it will have the QOS features that are applicable to voice services. Vivato intends to enhance and deploy those systems with Vivato beam forming technologies.
References [] Vivato Technical White Paper, Metropolitan Wireless LAN/Man Deployment. June 24, (www.vivato.com/metro/download/metrowirelesslan.pdf) About Vivato - Vivato delivers a complete family of innovative Wi-Fi infrastructure products, featuring Wi-Fi Base Stations, both indoor and outdoor. Vivato's base stations are packaged as a single integrated unit, including the planar phased array antenna and all of the electronics needed to run the Base Station. Simply supply Ethernet and power, and the Base Station delivers beams of Wi-Fi to a large area. For more information please visit www.vivato.com. Vivato is registered in the U.S. Patent & Trademark Office. All other product or service names are the property of their respective owners. Vivato Inc. 24 //4 rsr