Abstract: Preferred embodiments of this invention provide a base station and a terminal appropriate for a protocol for realizing a high performance and a low delay by relaying in a base station only if a direct transmission is not performed between terminals and omitting a data transmission channel for relaying if the direct transmission is performed. When a receiver terminal receives data directly from a sender terminal, the receiver terminal transmits a report of a direct receipt of the data to the base station. When the base station receives the report of the direct receipt of the data, the base station omits the data transmission channel for relaying.

Abstract: A data allocator which allocates data and redundant data for recovering the data. The data allocator has k storage groups, each of which includes m array files. Each array file includes multiple memory areas for storing the data and the redundant data on a block basis. A redundant group is formed which consists of k memory areas, each of which is selected from the same row of each one of k storage groups, and one of the k memory areas stores the redundant data and the remaining (k-1) memory areas store the data. The redundant data are uniformly allocated to m.sup.k sets of memory areas (D.sub.ij1, D.sub.2j2, . . . , D.sub.kjk) of the same rows of the storage groups, where j.sub.i (j.sub.i =1-m) is the number of the array file in each of the storage groups, and D.sub.kjk is the memory area belonging to k-th storage group and j.sub.k -th array file of the k-th storage group.