Interview Questions

Wireless systems

We saw that throughout the duration of the voice call in a conventional system, a circuit is reserved. This is how a call can be made.

But even when the call is not made, the telephone line is lying idle. This is not an optimal performance and is not returning money to the investment made by service provider.

Assume it takes Rs.40,000/- to lay and provide land line connectivity to a house. Even if the subscriber pays a rent/subscription of Rs.400/- it will take 100 months to recover the cost alone. Other maintenance and operational costs are not included yet.

To avoid this, the last mile connectivity should be made shared. And sharing is possible if the connectivity is wireless.

Also to lay and maintain a land line system, requires underground laying of cables and maintenance also adds up cost.

So natural choice was wireless networks.

As the wireless technology grew, they were sharing the network resources amongst the best possible way across subscribers who want to use the network, avoided maintenance issues in every subscriber premise/line and provided quicker return on investment.

As the wireless system provided roaming, subscribers started preferring the mobile way and that in turn drew technology advancement leading to world' largest and hugely successful technologies such as GSM, CDMA, 3G (UMTS, WCDMA) and WiMax. Already we are talking about 4G in Long Term Evolution (LTE).

So starting point for a wireless network is the necessity to provide mobility, reduce operating expenses and to provide global coverage through roaming services.

If you think of the above names, you will get to know that each of this technology provides the expected requirements and with success.

Underlying principle across these technologies is on the air interface (between the subscriber' hand phone to the Base Station). With improvements, each started providing higher data rates, convergence, advanced services, location based services, improved network performance and more number of subscribers.

Wireless call continues...