Introduction

The advent of advanced communication technologies in the past decades has ushered the era of information age. To date, the high-rate instant access to the media-rich information (e.g., online gaming and video on demands) and ubiquitous communications to each other (e.g., emails and social networks) have already become an integral part of our daily lives. As reported in [1], the average Canadian spends 18 h a week on the Internet, which has outpaced the time spent on watching TV.