# ITFDS: Channel-Aware Integrated Time and Frequency-Based Downlink LTE Scheduling in MANET
## 1 Introduction  
Industry 4.0 has now become reality with the support of advanced techniques in AI, distributed computing, and machine-to-machine (M2M) communication. One of the crucial problems in Industry 4.0 is how to strengthen the performance of mobile communication. In mobile ad-hoc networks (MANETs) and mobile computational grids (MCGs), devices communicate through the Wireless medium of mobile communication [1; 2; 3]. The 3G Partnership Program (3 GPP) has introduced the fourth generation (4G)-long term evolution (LTE) technology that supports multiple users for downlink with higher order modulation up to 64 Quadrature Amplitude Modulation (QAM) [4]. It is a multi-user version of the popular orthogonal frequency-division multiplexing (OFDM) digital modulation scheme called orthogonal frequency-division multiple access (OFDMA). The OFDMA used in LTE has the advantages of MIMO-friendliness, scalable bandwidth and robustness against multi-path fading [5]. In LTE downlink transmissions, a high data rate up to 300 Mbps is achievable using a scalable bandwidth of 5 to 20 MHz [6; 7; 8]. The 3 GPP specification defines that the downlink and uplink traffic are to be avoided by utilizing time division duplexing (TDD) and frequency division duplexing (FDD) [9]. However, multimedia applications strongly dominate LTE networks and may vary from live interaction and video conferencing to television. The resource scheduling in the LTE system for both uplink and downlink are managed by eNodeB and scheduled to various users deepening on the channel quality and service quality [10]. The domination of multimedia applications is due to their high transmission rate than any the other data formats. As the consequence, the traffic rate for mobile communications will be increased to a greater extent. Quality of service (QoS) should be guaranteed in terms of delay, quality and data loss by LTE scheduling for mobile multimedia applications [11]. QoS for any LTE system is directly dependent on the scheduling algorithm used. In the existing LTE scheduling, the scheduler in frequency domain packet scheduling exploits the spatial, frequency and multi-user diversity to achieve larger MIMO for the required QoS level [12]. For that, the scheduler considers channel conditions of all users upon possible MIMO modes to allocate the resource blocks (RBs) to users. There are several types of schedulers: channel unaware, channel aware or quality of service unaware and channel aware or quality of service aware [13]. The channel unaware schedulers are mostly used in wired networks, and their scheduling is performed by assuming the transmission medium as error-free and rigid. The channel aware/QoS unaware schedulers allocate the resources by analyzing the current channel conditions. Proportional fair (PF) [14] and PF-PF [15] are some of the channel aware/QoS unaware schedulers. PF-PF is the joint time and frequency scheduler. The channel aware/QoS aware scheduler considers both the channel quality and QoS required by user applications. It is mostly used in LTE systems to meet their performance requirements. The M-LWDF and EXP/PF are some channel aware/QoS aware schedulers [16]. Regarding time frequency scheduling, two levels of LTE scheduling for temporal and utility fairness were given in [17]. Later, earliest deadline scheduling was proposed in [18] for managing queues in the time domain. Packet prediction was emphasized in [19] to manage users in the time domain. In packet prediction, virtual queues are used to manage the queues under traffic. A scheduling algorithm for real-time traffic flow, which mainly concentrates on queue management and bandwidth allocation, was recommended in [20]. In LTE, a MAC scheduler sitting just above the physical layer [21] was used to categorize data packets that allocate resources upon traffic. The disadvantage of this method is the MAC scheduler allocates maximum resources to the GBR queue so non-GBR packets may suffer time delays.