## 1 Introduction  
The primary task in wireless sensor networks is data collection. Recently, many research works have investigated the data collection process, especially for large-scale networks, to address the challenges related to this process, such as energy consumption, connectivity, and latency. This primary task leads researchers to find practical solutions such as introducing mobility to this kind of networks [1; 2; 3; 4; 5; 6; 7; 8; 9], because of the great revolution in robotics that may be useful for wireless sensor networks to solve problems related to connectivity, routing and data collection [10]. The mobility in wireless sensor networks also solves the problem of the quick energy dissipation of nodes in the vicinity of the sink in the traditional wireless sensor networks with static sinks due to their role in forwarding data to the sink [11]. However, by making a collector node a mobile node we can help distribute the energy consumption in the network. In this study, we assume that the concerned mobile node is the sink. The mobile sink (MS) moves throughout the network and passes by sensor nodes to collect the sensed data from them. The strategy of using mobility in wireless sensor networks improves the connectivity of the network by reaching the isolated nodes. For large-scale wireless sensor networks, many research works propose dividing the network into clusters (cluster-based wireless sensor networks). Each cluster is composed of one cluster-head(CH) and a group of cluster members (CMs) [12; 13; 14]. CMs send the sensed data to their CH. When the MS arrives at the CH vicinity, the CH transfers or forwards the sensed data of its members to the MS. The aim of using a cluster-based wireless sensor network is to reduce the energy dissipation in the network, and thus to extend the network lifetime. Besides, using the cluster-based architecture helps to reduce the latency of the tour length of the MS in the network by visiting only CHs rather than visiting all sensor nodes. In addition, the trajectory length of the MS is considered a factor which affects the latency of data collection [15]. When the MS enters the radio range of a CH, the CH starts transferring data to the MS. In some cases, due to the speed of the MS taking into consideration the amount of data to be transferred from the CH to the MS, the CH can estimate that the transfer of data will not be completed in one single hop communication with the MS. Therefore, a continuous connectivity mechanism must be integrated into the transmitter node, which is the CH, to route the data to the receiver, which is the MS while it is moving. To do so, a handover mechanism is proposed for cluster-based wireless sensor networks. The handover mechanism is widely used in cellular networks to ensure the connectivity and the continuity of delivering data in a session between the transmitter and receiver without data loss and interruption, in the case where the channels are changing [16]. Introducing the handover mechanism in cluster-based wireless sensor networks to route the data, is considered a challenge because of the hierarchical architecture of the network and the need to control the handover mechanism by enabling some specific nodes to perform the handover process. In addition, some other points must be considered in this kind of networks such as the data delivery rate, energy, the speed of the MS, the end-to-end delay, the handover process delay and its influence on the end-to-end delay. In this paper, we propose a cross-layer routing for mobility support protocol based on a handover mechanism in multi-hop communication (CLR-MSPH for short). Our proposed protocol is based on predicting the suitable relay nodes depending on the trajectory of the MS. The design of the proposed mobility support protocol CLR-MSPH allows the network layer and the MAC layer to cooperate and exchange information messages to ensure a better routing and handover mechanism in the cluster-based wireless sensor network. Our proposed CLR-MSPH is originally based on the BMAC protocol.