WiMax deployments can incorporate mesh technology to support multiple access points over non-line of sight networks. Mesh technology is very useful for wireless systems located in areas where numerous physical obstructions impede the transmission of signals. This is not a new technology and has been widely used in the deployment of WiFi networks. Mesh technology is also widely used for military purposes to ensure constant and uninterrupted radio communication between base unit facilities.
WiMax mesh networks can be deployed in highly urbanized areas where buildings, houses and other physical obstructions prevent line of sight transfer of signals. Suburban and countryside WiMax networks can also deploy mesh technology to skirt over natural barriers such as hills, trees, or rows of houses. The capability of a mesh network for delivering distributed signals to subscribers makes it an ideal configuration for carriers using WiMax technologies. Their subscribers will not experience spotty signals or service interruptions caused by physical obstruction.
In a WiMax mesh network, a main wireless backhaul circuit could be the source of the entire bandwidth for a given area. Because modern neighborhoods are quite congested, meshing enables those far away from the main backhaul to get signals from other circuit networks distributed in the locality. It works like the relay system of radio stations. Access points however can be located over the rooftops of subscribers or on buildings or stop light signals if the mesh network is within a city. Through this technology, WiMax connectivity would be more stable and will not be too reliant on a single line of sight tower.
Most often OFDM or orthogonal frequency-division multiplexing is being associated as the similar of discrete multi-tone modulation and Coded OFDM. OFDM is actually part of the transmission schemes circle which is known as the multi-carrier modulation. The principle behind is that the data stream is being chunked into smaller bit rate and then they are being modulated using another carrier which is known as subcarrier.
Multi modulation schemes play a big part in eradicating inter- symbol interferences. This is made possible by producing large symbol time that is large enough to cause channel-induced delays that are being spread in the wireless channel. This is directly proportional to the symbol duration then so the symbol duration created is so little that it is rendered as insignificant.
OFDM or orthogonal frequency-division multiplexing is a good example of multicarrier modulation. In here the subcarriers are actually being chosen in a way that everything is orthogonal with each other in coincide with the symbol duration. And since the set up is in this way, it avoids the overlapping of the subcarriers which minimize the ICI or the inter carrier interference. It is important to note that the frequency synchronization should be so precise. Any deviation from the frequency of the subcarriers can cause them to become non-orthogonal with each other and this will be the cause of ICI.
Though OFDM is quite susceptible to the Doppler shift as well as to the frequency synchronization, still it can actually adapt with ease to damaging conditions of the channel. It is also strong enough when interacting with narrowband channel interferences. And these are just one of the reasons why OFDM is very efficient.