Abstract
This paper demonstrates the use of Universal Software Radio Peripheral (USRP), together with Raspberry Pi3 B+ (RP3) as the brain (or the decision making engine), to develop a distributed wireless network in which nodes can communicate with other nodes independently and make decision autonomously. In other words, each USRP node (i.e., sensor) is embedded with separate processing units (i.e., RP3), which has not been investigated in the literature, so that each node can make independent decisions in a distributed manner. The proposed testbed in this paper is compared with the traditional distributed testbed, which has been widely used in the literature. In the traditional distributed testbed, there is a single processing unit (i.e., a personal computer) that makes decisions in a centralized manner, and each node (i.e., USRP) is connected to the processing unit via a switch. The single processing unit exchanges control messages with nodes via the switch, while the nodes exchange data packets among themselves using a wireless medium in a distributed manner. The main disadvantage of the traditional testbed is that, despite the network being distributed in nature, decisions are made in a centralized manner. Hence, the response delay of the control message exchange is always neglected. The use of such testbed is mainly due to the limited hardware and monetary cost to acquire a separate processing unit for each node. The experiment in our testbed has shown the increase of end-to-end delay and decrease of packet delivery ratio due to software and hardware delays. The observed multihop transmission is performed using device-to-device (D2D) communication, which has been enabled in 5G. Therefore, nodes can either communicate with other nodes via: (a) a direct communication with the base station at the macrocell, which helps to improve network performance; or (b) D2D that improve spectrum efficiency, whereby traffic is offloaded from macrocell to small cells. Our testbed is the first of its kind in this scale, and it uses RP3 as the distributed decision-making engine incorporated into the USRP/GNU radio platform. This work provides an insight to the development of a 5G network.
Highlights
Fifth generation (5G) is a promising next-generation cellular network armed with new features, device-to-device (D2D) communication that enables direct communication between devices without going through base stations (BSs)
In a testbed with separate processing units, each femtocell node is embedded with a separate processing unit, namely Raspberry Pi3 B+ (RP3), as shown in Figure 4b
The total delay is higher in RPU, and it increases as the number of hops increases, the total delay increases from 0.024102s for a single hop to 0.10566s for five hops in processing unit (PCU), and from 0.02992 s for a single hop to 0.18924s for five hops in RPU
Summary
Fifth generation (5G) is a promising next-generation cellular network armed with new features, device-to-device (D2D) communication that enables direct communication between devices without going through base stations (BSs). This helps to offload traffic from macrocell (MC). Traffic offloading from backbone routes and the central controller to distributed nodes is investigated in [13,14], the transmission delay is predicted based on channel states in [15], and the feasiblity of D2D in 5G environment is investigated in [16]. The FC BSs can coordinate and communicate among themselves via D2D if they are within each other’s transmission range, and this helps them to:
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