Moving elevator-cell system in indoor buildings

To plan efficient future PCS networks, indoor environments as well as outdoor environments must be considered. Users typically exhibit vertical motion through elevators and horizontal motion on building floors in indoor environments. A user on the way into or out of an elevator may experience difficulty in communicating with a base station (BS) due to large signal attenuation caused by the metal structure of the elevator, especially the door. The user also may suffer from handoffs as the user passes several floors during the course of a call as the elevator moves. It is necessary to overcome these problems related to elevators for indoor cell planning. In this paper, a nonmoving and two moving elevator-cell systems for a building are considered. The undesirable inter-floor handoffs while the user is inside the elevator of the nonmoving elevator-cell system (N-system) are eliminated by introduction of two moving elevator-cell systems: a simple moving elevator-cell system (S-system) and a proposed moving elevator-cell system (P-system). The S-system does not seamlessly maintain calls between an elevator and adjacent floors due to insufficient time when the elevator is open to complete the handoff, while the P-system seamlessly maintains calls using a macro diversity with a distributed antenna scheme. The movements of an elevator and users are modeled and the P-system is compared with the S-system in terms of the required number of channels. The P-system reduces the total required number of channels compared with the S-system under heavy traffic conditions. The elevator-cell system and modeling results can be used in the design of future indoor wireless systems.