An adaptive popularity tracking algorithm for dynamic content caching for radio access networks

The users' requests for online objects in mobile networks are characterized by fast varying dynamics caused by user mobility and diversity of users who produce contents. Conventional popularity methods cannot efficiently handle such strong dynamic requests of users, because they pay little attention to the time-varying user behavior which contributes to the growth and fading of online media files. To handle this issues, this paper proposes two schemes, including sensing the popularity variation speed of the hot contents and adaptively adjusting the popularity tracking speed of the cache algorithm. For the first one, we make use of the pseudo popularity acceleration in a time window to calculate the shifting speed of hot objects. With the obtained shifting speed can we adaptively adjust the popularity tracking speed of our previous EWMA method. Note that our adaptive EWMA method can achieve nearly the best performance without prior knowledge regarding the shifting speed of hot objects requested by users. Simulations confirm that our adaptive EWMA method significantly outperforms conventional popularity tracking methods.