| Author | Goonewardena, Mathew Pradeep |
| Call Number | AIT Thesis no.ICT-11-02 |
| Subject(s) | Cognitive radio networks
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master
of Engineering in Information and Communications Technologies, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ICT-11-02 |
| Abstract | The thesis addresses the problem of power allocation of the down-link in central base
station based cognitive radio network.
Unlike the primary network which has fixed resources assigned, in a cognitive
radio network the resource availability for the secondary users are random processes
determined by primary user behavior. Consider an under-lay cognitive radio network
where the primary user has the priority and cognitive radio network may use only the
idle channels. In such a scenario the cognitive radio network loses the symbols that
are being transmitted during that time slot when the PU takes the channel and if the
error correction code cannot handle the length of symbol loss. Further, in the next
time slot, the cognitive radio network have to select again, a free channel to continue
the communication or in the event that all channels are occupied by primary users
and other secondary users it enters an indefinite waiting process. Thus it is intuitive
that the time averaged data rate of the cognitive radio network not only depends
on the channel characteristics of signal to interference and noise ratio (governed by
Shannon’s law) but also on the channel’s likelihood of being taken over by the primary
system during the transmission. Cognitive radio networks, with the spectrum sensing
capabilities inherent to them, have the ability to characterize the activity statistics of
PU’s.
In this thesis two main models, namely equivalent noise of primary user activity
level (ENPA) and effective bandwidth of primary user activity level (EBPA), are
proposed to represent PU activity in a channel. Based on these models a combined
model is also introduced. Then these models are employed in a proposed cognitive
radio environment to derive power allocation schemes for the network downlink. These
schemes are compared with the traditional water-filling algorithm and the risk-return
model and are shown to achieve higher average rates than the water-filling algorithm
and similar or higher gains compared the rate-loss model. |
| Year | 2011 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ICT-11-02 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Information and Communication Technology (ICT) |
| Chairperson(s) | Rajatheva, R.M.A.P.; |
| Examination Committee(s) | Zeghlache, Djamal;Chahed, Tijani;Poompat Saengudomlert;Ahmed, Kazi M.; |
| Scholarship Donor(s) | The Government of Finland;Telecom Sud Paris, France; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2011 |