The layered cell configuration, in which a large number of small cells are set in a macro-cell coverage area, is attracting much attention recently as a promising approach to handle the rapidly increasing mobile data traffic. In this configuration, cells of various sizes, from macro to small, are placed in various locations, so that the variation in the number and the distribution of the users among cells becomes much wider than in conventional macro-cell homogeneous networks. Therefore, even in the layered cell configuration, the users in the cell with many users and low received signal quality may experience low throughput especially at cell edge. This is because such users experience both low spectral efficiency and few radio resources. In order to resolve this issue, a lot of techniques have been proposed such as load balancing and cooperative multi-point transmission. In this paper, we focus on scheduling priority control as a simple solution that can also be used in combination with load balancing and coordinated multi-point transmission. We propose an adaptive scheduling priority control scheme based on the congestion and user distribution of each cell and clarify the effect of the proposed method by computer simulations.

One way of accommodating multimedia traffic having various transmission rates is to use multicode transmission in CDMA cellular systems. A multicode user, however, corresponds to locally concentrated single-code users, and the simultaneous transmission of multiple signals causes non-uniform traffic on cellular systems. We evaluate the performance of multicode transmission in CDMA systems in terms of call blocking and communications quality. We also estimate the number of receivers and searchers needed in a base station. Our previously proposed dynamic cell configuration (DCC) scheme reduces the adverse effects of non-uniform traffic in CDMA systems. In the present study, we found that the use of DCC for voice/data integrated traffic using multicode transmission reduces call blocking and improves communications quality for both voice and data users.