Why the Mesh network can not have a good performance?

Due to Wireless Mesh Network is an Ad-Hoc network, there are some factors that could effect such a Wireless CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) environment. And there are: 1. number of nodes, 2. distance, 3. RSSI (Received Signal Strength Indication)

1.Normally, the more Mesh nodes installed, the more users share the same wireless backhaul bandwidth. It is suggested that around 4 to 8 nodes share the same Mesh backhaul, or add one more Gateway whenever the nodes grows. For example, 4 relay, 1 gateway, etc.

2.The longer the distance, the weaker the signal strength. Not only for backhaul but also for wireless clients. Remember, a standard Wireless clients won’t have the high-power capability to sending out the packets to the AP. So whenever planning the Mesh network, the distance for node to node, you will need to consider the capability for a wireless clients as well. In a normal wireless network a wireless clients can not exceed 400 meters (LOS, line-of-sight), to provide a roaming wireless mesh network 400 meters is our suggested Mesh node to node distance. Of course, the real installation may vary and will need the at-site testing.

3.The RSSI value or sensitivity reading in the wireless system. Be reminded, CMSA/CA network is a contention network, without doubt, the more users in this network, the worse the performance. And for wireless, there will have another point - The strength of the wireless signal that heard from the transmitter. The stronger the transmit power does mean the signal can be transmitted longer.

Example, say node A, node B, node C, A is in the central, and B is 300 meters to A, C is 400 meters to A. C and A is 200 meters away, all line-of-sight. To have the optimal performance, it is suggested to make the three nodes hear each other in the same RSSI value (or as close to each other as possible). Example like this, A can hear B and C at -45db and -50db, B can hear A/C at -42db/-48db, C can hear A/B at -50db/-48db. The biggest one and the smallest one is in 8db. If there is a reading over 10db or more, there could be performance issues in the whole network.

The central point with more powerful transmission does not mean a better performance. Also, you can tell does the cable or wiring make a serious loss from these readings.