Search

This paper aims at construction of a large-capacity multimedia wireless communication system, and proposes a multimedia adaptive modulation with dynamic channel assignment (M-AMDCA) system. The proposed system controls the modulation parameters and the slot assignment according not only to the propagation environment but also to the requirements regarding the transmission such as the quality and the bit rate. The slow adaptive modulation method is applied to real-time media such as voice and video, so that a large-capacity system is realized while satisfying the bit-rate requirement. On the other hand, the fast adaptive modulation method is applied to non-real-time media such as data, so that a high throughput is realized by controlling the modulation parameters with high speed within the assigned band. The performance of the proposed method is analyzed for mixed voice, video, and data models by computer simulation, and satisfactory performance is verified for each medium. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(6): 49–58, 2001 [ABSTRACT FROM AUTHOR]

Provides information on a study which proposed a time-division multiple-access-based adaptive modulation with dynamic channel assignment (AMDCA) to achieve high-capacity communication systems. Concept of AMDCA; Simulation results; Conclusion.

This paper aims at the realization of a large-capacity mobile communication system in the microcellular environment and proposes adaptive modulation with dynamic channel assignment (AMDCA) where the idea of dynamic channel assignment (DCA) is introduced into the slow adaptive modulation system. In the proposed system, the received average signal power-to-noise/interference power ratio [C/(N + I)] is measured for each TDMA (time division multiple access) slot. The choice of idle slots in DCA and the choice of applicable modulation parameters for the slots are made in parallel. Thus, wireless frequency resource assignment and the setting of the modulation parameters take place at the same time. This reduces the effect of the space–time distribution of the traffic in DCA and also reduces the effect of the spatial distribution of the received power in the slow adaptive modulation system on the geographical difference of the blocking probability of the users. The performance of the proposed method is evaluated by a computer simulation, and it is verified that a capacity approximately 3 times larger can be realized compared with conventional fixed-channel assignment in fixed QPSK in the case of voice transmission. © 1998 Scripta Technica, Electron Comm Jpn Pt 1, 82(1): 55–64, 1999 [ABSTRACT FROM AUTHOR]