Depl oyment Chall enges
High-performance wireless infrastructure is not easy to design and deploy, and professional wireless equipment is a considerable investment, Coffman said. “To ensure the success of any wireless surveillance installation requires intelligent planning from the start. You must perform site surveys, for example, to determine any issues involving LoS obstructions, RF environments, distances and access to camera sites.”
Major challenges in implementing wireless mesh networks include deployment and training, Mahishi said.
Deployment often requires coordinating resources that are not under the direct control of the customer or integrator, such as public utilities, telephone, cable and private companies, Coffman said. “From a technical point of view, ensuring LoS between nodes is essential. Design work may occur in the winter months when foliage is minimal; the spring-time foliage, however, can obstruct LoS. Such issues can be dealt with by going around obstructions; some projects call for the construction of a tower or mast.”
Securing power and gaining access to camera locations can also be challenging, if the customer does not “own” the light poles or buildings where cameras are to be mounted, Coffman continued. “Solar or power generators may be required to power remote installations. When allocating budgets and finalizing network design, the provider should consider all contingencies and discuss them with the end user.”
The learning curve for deployment of a wireless mesh network is longer than general wireless apparatus, Damato added. “Previous wireless and IT management experience, as well as previous experience with a particular manufacturer's mesh system, will assist with how to properly use specific diagnostics tools.“
Mesh topologies can involve redundant path scenarios which will require configurations to eliminate loops in the communication, Damato continued. “If a mesh system manufacturer does not simplify the interface for setup, it can be more difficult to integrate the system. On the other hand, if they simplify it too much, it becomes easier to cause loops. There should be tools and diagnostics within the GUI with which a user can determine the correct route(s) for the wireless c ommu nication with in the network.”
No Interoperab ility
Currently, there is no industry stand a rd for wire less mesh networks. All mesh solutions are proprietary, and wireless gear from different providers cannot be properly integrated together, Mahishi said. “However, IEEE 802.11s is very close to being ratified by IEEE and may provide this support in the future.”
No Silver Bullet
Most of the confusion and unrealistic expectations from wireless mesh networks arise from confusion between data rate and throughput; real throughput in noisy environments; throughput as the number of mesh nodes increases; and backhaul link throughput.
“Throughput across the wireless network is a common misconception. If the node has two radios, users assume that there is 100 Mbps combined. In reality, in turbo-mode channels, each radio can independently offer up to 50 Mbps, depending on the frequency, environment and local regulations,” Damato explained.
“The specifications should be closely examined. Often, a ‘signal rate' is thought to be the throughput over the air. The signal rate refers to the speed of connection between radios, whereas the throughput is the overall pipe capacity based on specs such as the signal rate, signal strength, possible interfering sources and other environmental factors,” Damato said.
Vendors should articulate clearly real-life performance metrics under various deployment scenarios to minimize confusion for their clients and better educate end users on realistic expectations in real-life settings.