Wireless VOIP
Wireless-VOIP.Com

The core advantage of wireless mesh networks is their inherent ability to form a network on power up. Watch what happens in Fig 1, when the mesh nodes power up (green LED on box turns on). The nodes hear each other's broadcast and form a network. Also watch what happens when a node fails and how the nodes discover an alternate routing path. This healing is fully automatic.

Over the years, wireless mesh networking has seen three unique deployments based on radio technology, each incorporating iterative improvements allowing for greater scalability and higher network performance - both throughput and latency. This early stage of pre IEEE standard technological development is known as first Generation of Wireless Mesh. The following deployments are briefly described of various configurations of first generation Wireless Mesh Networking:

Winrich Hoseit of Cologne, Germany first described the "DIRC technology" (digital inter relay communication) with PCT patent No. DE 197 37 897 and DE 197 33 586. Because transmitted radio waves always interfere, the ratio of carrier to interference first had to be worked out. Hoseit also discovered how to prevent latency by transmitting single symbols rather than digital packages. (symbol stream switching). Each node collaborates with its neighbor-nodes via a control channel (CCH) to choose the frequency, time and energy with which to transmit each symbol. Only the final destination "understands" the application with the lowest possible latency.

Configurations

1-Radio Mesh

As shown in Figure 3, this configuration uses one radio channel both to service clients and to provide the mesh routing path back to a wired or satellite link (backhaul). The single mesh radio, provides both services - client access and backhaul. Comparative performance analysis indicates this architecture provides the worst performance of all configurations, because backhaul and service compete for bandwidth. Also all single radio mesh architectures suffer from the send-receive-wait cycle shown in Figure 3. Since there is only radio, the mesh node has to listen, then send, then listen again. This intermittent stop-and-go behavior adversely affects network performance especially if the destination is far away and the traffic has to be re-transmitted ("hop") across many intermediate nodes first.

Tags:  radio nodes first network performance wireless configurations single latency backhaul