Wireless Network Optimisation

Mike Morgan

Categories of Wireless Device

➲ Fixed ● Physically fixed in position e.g. Antenna

mounted on tower or rooftop● Commonly used for broadband communications

➲ Portable● Stays in place while being used, but can be

picked up and moved to another location➲ Mobile

● In motion during use

Fixed Wireless Network Types

➲ Point to Point● Bus Topology

➲ Point to Multipoint● Star Topology

➲ Consecutive Point● Ring topology: some redundancy● Hamiltonian Cycle

➲ Mesh● Mesh Topology: better redundancy● Design problem is very complex

Mesh Networks

➲ How many different ways can these nine devices be connected?

➲ Which one is the best?

Design of Mesh Networks

➲ Some devices perform the task of 'relaying' data on behalf of others.

➲ The equipment needed for relay devices is normally far more expensive than for ordinary terminals.

➲ Two design goals:● The number of relays used ought to be kept to a

minimum.● The network should provide adequate

redundancy and be able to handle traffic demands.

Heuristics

➲ It is not possible to evaluate all possible mesh structures within a useful time frame

➲ A smaller subset of possible network designs must be evaluated. Optimal answers cannot be guaranteed.

➲ How might it be possible to select good designs for evaluation among so many alternatives?

Construction methods

➲ Greedy construction searches build the network component by component.

● Start with nothing and add relays in until all objectives are satisfied.

● Start with a maximum number of relays and drop as many as possible without violating constraints

➲ These searches can be adapted using iteration, random factors and memory based techniques.

Perturbation Methods

➲ Make minor alterations to a current solution in the hope of finding an improvement.

➲ Also may be adapted using random factors and memory.

➲ Useful as a means of improving already promising solutions