Abstract: This article proposes a hybrid algorithm for spectrum
allocation in cognitive radio networks based on the algorithms
Analytical Hierarchical Process (AHP) and Technique for Order of
Preference by Similarity to Ideal Solution (TOPSIS) to improve the
performance of the spectrum mobility of secondary users in cognitive
radio networks. To calculate the level of performance of the proposed algorithm a
comparative analysis between the proposed AHP-TOPSIS, Grey
Relational Analysis (GRA) and Multiplicative Exponent Weighting
(MEW) algorithm is performed. Four evaluation metrics are used.
These metrics are accumulative average of failed handoffs,
accumulative average of handoffs performed, accumulative average
of transmission bandwidth, and accumulative average of the
transmission delay. The results of the comparison show that AHP-TOPSIS Algorithm
provides 2.4 times better performance compared to a GRA Algorithm
and, 1.5 times better than the MEW Algorithm.
Abstract: Spectrum handover is a significant topic in the
cognitive radio networks to assure an efficient data transmission in
the cognitive radio user’s communications. This paper proposes a
comparison between three spectrum handover models: VIKOR, SAW
and MEW. Four evaluation metrics are used. These metrics are,
accumulative average of failed handover, accumulative average of
handover performed, accumulative average of transmission
bandwidth and, accumulative average of the transmission delay. As a difference with related work, the performance of the three
spectrum handover models was validated with captured data of
spectrum occupancy in experiments performed at the GSM frequency
band (824 MHz - 849 MHz). These data represent the actual behavior
of the licensed users for this wireless frequency band. The results of the comparison show that VIKOR Algorithm
provides a 15.8% performance improvement compared to SAW
Algorithm and, it is 12.1% better than the MEW Algorithm.
Abstract: This paper develops a multiple channel assignment
model, which allows to take advantage of spectrum opportunities in
cognitive radio networks in the most efficient way. The developed
scheme allows making several assignments of available and
frequency adjacent channel, which require a bigger bandwidth, under
an equality environment. The hybrid assignment model it is made by
two algorithms, one that makes the ranking and selects available
frequency channels and the other one in charge of establishing the
Max-Min Fairness for not restrict the spectrum opportunities for all
the other secondary users, who also claim to make transmissions.
Measurements made were done for average bandwidth, average
delay, as well as fairness computation for several channel
assignments. Reached results were evaluated with experimental
spectrum occupational data from captured GSM frequency band. The
developed model shows evidence of improvement in spectrum
opportunity use and a wider average transmission bandwidth for each
secondary user, maintaining equality criteria in channel assignment.