This chapter presents cooperative relaying networks that are helpful in Internet of Thing (IoT) applications for fifth-generation (5G) radio networks. It provides reliable connectivity as the wireless device is out of range from cellular network, high throughput gains and enhance the lifetime of wireless networks. These features can be achieved by designing the advanced protocols. The design of advanced protocols plays an important role to combat the effect of channel fading, data packet scheduling at the buffered relay, average delay, and traffic intensity. To achieve our goals, we consider two-way cooperative buffered relay networks and then investigate advanced protocols such as without channel state information (CSI) i.e., buffer state information (BSI) only and with partial transmit CSI i.e., BSI/CSI with the assistance of one dimensional Markov chain and transmission policies in fading environment. The outage probability of consecutive links and outage probability of multi-access and broadcast channels are provided in closed-form. Further, the buffered relay achieves maximum throughput gains in closed-form for all these protocols. The objective function of throughput of the buffered relay is evaluated in fractional programming that is transformed into linear program using standard CVX tool. Numerical results show that our proposed protocols performance better as compared to conventional method studied in the literature. Finally, this chapter provides possible future research directions.
TopIntroduction
The cooperative relaying communication (CRC) is one of most promising technology in Internet of Things (IoT) applications for fifth-generation (5G) networks (BenMimoune & Kadoch; Liu & Ansari, 2017). In IoT, CRC exploits the features of mutual cooperation along with relaying technologies to improve the spectral efficiency of cellular networks, to enhance the coverage area as the wireless portable devices are out of range from cellular networks, and to reduce the battery depletion problem. It can support tremendous access in cellular network for indoor environment and outdoor environment in real time.
Figure 1. Cooperative Relaying Technology for 5G radio networks and IoT applications: (a) the multihop relay network; (b) the heterogeneous relay scenario; (c) the relay connects to donor base station (BS); (d) the relay-assisted D2D communication; and (e) Public service by smart bus (SB) and the relay-assisted high-speed smart train (HST).
The relay in IoT applications (IoTAs) is the state-of-art for 5G radio networks that accommodates various physical things such as sensor nodes, smart mobile phones, home appliances, healthcare gadgets, machines, and intelligent furniture. The communications road maps of such autonomous things are essential for bonding them together to form the IoT. All these things are linked through a network which is referred to as IoT devices (IoTDs). The deployment strategies of the relay in the IoT applications for 5G network are shown in Fig.1 (BenMimoune, & Kadoch, 2017). The relay deployment scenarios in the IoTAs are summarized as follows: (a) the multi-hop relay can be used to extend the radio links between base station (BS) and user into more than two-hop, and performances of each of hop are expected to be better than direct link in cellular networks. (b) Heterogeneous relay is attractive technique to provide smart coverage to local area via WiFi technology. (c) the relay connects to several base stations (BSs) to achieve high throughput gains and balance the network loads across the BSs. (d) performance of device-to-device (D2D) communication is limited by excessive interference and poor propagation channel. These challenges can be minimized by providing relay-assisted links. The relay can efficiently improve the performance of D2D communication. (e) mobile relay stations are mounted on public buses and high speed smart train (HST) vehicles to provide better connectivity and compensate the vehicular penetration losses. In modern era, instruments in factory utilize the features of IoT to improve the performance and capability of factory and farm operations (Liu & Ansari, 2017). The relay in IoTAs also, provides wireless access links to the persons travelling in high speed trains to achieve highest possible transmission rate.
TopBackground
The CRC plays an important role in IoTAs for 5G networks by providing low-powered relay to increase the performance gains of wireless networks in real time applications. It includes various objective parameters for analysing the performance gains of relay networks such as transmission power, energy efficiency, throughput, average delay, low interference to prime networks, and distanced from network coverage. In IoTAs, the relay exploits several relaying protocols to receive the incoming information from the source and after some electronic processing, it sends the information to destination via available wireless links. The signalling protocols are summarized as follows.
- 1.
Amplify-and-forward (AF) Relaying Protocol: In the AF relaying scheme, the relay amplifies the incoming noisy signal from the source and retransmits it to the destination (Beaulieu & Hu, 2006).
- 2.
Decode-and-forward (DF) Relaying Protocol: In the DF method, the signal received from the source by the relay is decoded in the first phase, after that the relay retransmits the re-encoded information to the destination (Laneman et al., 2004).
- 3.
Compress-and-forward (CF) Relaying Protocol: In the CF scheme, the relay allows to compress the incoming signal from the source and encode it into new packet that is sent to the destination (Akhbari et al., 2009).
- 4.
Randomize-and-forward (RF) Relaying Protocol: In the RF method, the relay has freedom to receive random data packet from the source and then it uses different codebooks to forward the data packets to destination (Shafie et al., 2016).