Spectrum Pooling
Recently Sunil Mittal of Bharti Airtel had give a proposal for spectrum pooling where in telecom companies will create a jointly owned company to operate this spectrum pool. Spectrum pooling is a spectrum management principle whereby licensed (primary) users put their unused spectrum into a pool from which secondary users can rent spectrum. It is significant because of three reasons. First, the spectrum is a scarce commodity as the government releases it in small tranches, with the major part remaining with the Army; second, it is very expensive and third, it’s usage is very lopsided.
It can be understood by an example. Let us take a scenario where Operator A is short of spectrum and Operator B has spare spectrum which is unutilized. In an existing arrangement companies use only the spectrum assigned to them.Hence Owing to shortage of spectrum Operator A’s consumers would suffer network congestion and call drops, while B would be having expensive spectrum which was won in an auction and now it is idle earning no revenue. A common pool of spectrum would avert this scenario where Opeartor B can rent its unused spectrum to Operator A.
Cognitive Radio Technique
Spectrum polling is generally implemented through cognitive radio technique. The notion of spectrum pool represents the idea of merging spectral ranges from different spectrum owners into a common pool. From this spectrum pool which is hosted by the licensed system, rental users may rent spectrum resources during idle periods of licensed users. Hence receivers in a spectrum pooling rental system must be able to detect temporarily idle frequencies very fast which brings the role of cognitive radio technique.
A cognitive radio is a software defined radio (SDR) that additionally senses its environment, tracks changes and reacts upon its findings. A CR is an autonomous unit in a communications environment. In order to use the spectral resource most efficiently, it has to:
- be interference sensitive
- comply with some communications etiquette
- be fair against other users
- keep its owner informed
Rental users through spectrum pooling obtain access to spectral ranges they have not yet been allowed to use, and the actual license owners generate new sources of revenue for a spectrum they have not been using intensively anyway
Advantage of Spectrum Pooling
There are several advantages of Spectrum Pooling. Firstly, the spectrum sharing will help operators address issues pertaining to spectrum shortage, network coverage and quality of service. Secondly, it is advantageous while sharing between a large operator (high revenue market share [RMS] and coverage with a congested network and a small operator (low RMS) with under-utilised network/ limited coverage. While the large operator will be able to address capacity and congestion issues, the small operator will benefit from the better network coverage of the large operator. For instance, if two small operators (low RMS) with limited coverage get into a spectrum sharing agreement, it will lead to better population coverage at a significantly lower capex and opex. In addition, by pooling spectrum, operators will be able to achieve higher spectral efficiency and higher network capacity as compared to non-pooled spectrum. Spectrum sharing may also help some operators launch new technologies such as 4G services.
