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The day is near where 802.11n is going to be ratified. All schools, hospitals, business – name a place with Wi-Fi and it would be 802.11n based. Deploying 802.11n is a challenge by itself because of its MIMO nature and multiple path of access to a Wireless Network. It is very important to have a stable reliable Wireless Network to support mission critical applications. Deployment of a high speed mission critical Wireless Network is very difficult especially in an area where a lot of people are accessing the Wireless Network and expecting good speeds out of it. Imagine a situation in huge auditorium of a Stock exchange where hundreds of users are accessing the Network and doing huge mission critical file transfers at High Data rates. This is a very dense environment where each and every person needs to be connected at high speeds.
Unfortunately the traditional Microcell architecture is not a solution for this kind of application. Let us take for example a closed area of 50 feet by 50 feet. In a dense environment there can be about 50 clients connected at the same time to the Network and access critical data from the system. In Microcell architecture, the most likely deployment scenario will be about two access point in this area that are servicing in adjacent channels. Since fifty feet is an area that can be serviced and seen by almost all access points/clients irrespective of setting the power to a low value, the clients can be connected to either one of the access point at any given juncture of time. The Microcell Network architecture has no way to control what clients are connected to which access points. This may result in the client ping ponging between the access points causing unnecessary hand-offs and as a result important data loses. The best way to avoid these kinds of ping ponging situations in Microcell architecture is to use a single access point in a single channel in the enclosed room. What would that lead too? The wireless connection may be maintained without ping ponging – but the performance is degraded by 100% or sometimes even higher depending on the size of the room and the number of access points that are used. Imagine a client giving only 6 Mbps of throughput where as the theoretical max is 300 Mbps! In addition to this the multi path in 11n causes a problem and may result in a lot of collisions in a single channel.
The only way to get around this problem is to make use of single channel architecture with channel stacking or channel layering in an area where very dense deployments are needed. Meru Networks single channel architecture can achieve reliable wireless communication and speeds 4 times that of the Microcell systems. The Meru Architecture allows for deployment in a single-channel blanket, as opposed to the micro-cell approach, due to mitigation of co-channel interference and contention. Thus deployment in a single-channel, besides being significantly easier to plan, deploy and operate, preserves RF spectrum. This addition spectrum can then be utilized to provide additional bandwidth through increased spectral diversity.
In a very dense environment channels can be stacked or layered one over the other to provide blankets of Wireless Network in the given area. Clients, once associated, will tend to stay within a blanket and roam seamlessly. The system has the ability to influence clients’ choice of which blanket to join (these will be seen as separate APs – unique BSSIDs on separate channels). So in the very similar example of a case where in a room 50 clients need to be serviced by the Network, the channels can be layered into different blankets and the Meru Architectures load balancing algorithm determines in which blanket each client stays and in turn provides with 4 times the total throughput when compared to Micro Cell systems at the same time maintaining a very stable Network. 802.11 n promises high throughput Networks with reliable connections and that is only possible with a Channel Layered approach with Load Balancing.
