Low Earth Orbit (LEO) satellite communication is critical for widespread Internet of Things (IoT), especially for small data transmissions. Conventional Access Class Barring (ACB) and Random Access Procedure (RAP) schemes, originally designed for stochastic terrestrial channels, are ill-suited for LEO networks as they fail to exploit the deterministic nature of satellite trajectories. To address this critical gap, we propose Channel and Timing-Predicted (CTP) ACB that dynamically prioritizes User Equipment (UEs) by exploiting the high predictability of LEO satellite channels, thereby optimizing resource allocation and improving energy efficiency. We introduce an optimized Random Access Channel (RACH) period to balance system throughput with individual UE service rates. Through comprehensive simulations, we demonstrate that CTP ACB substantially improves throughput, resource utilization, and energy efficiency. Regarding information freshness, while CTP ACB introduces a marginal scheduling delay in low-density scenarios, it significantly reduces the mean AoI by approximately 30% in high-density massive IoT networks by effectively mitigating access congestion. These findings highlight the necessity of trajectory-aware designs in next-generation NTN-IoT standards.

The variety of low latency applications in 6G makes the issue of maintaining data freshness increasingly important. However, due to battery life limitations, User Equipment (UE) should also apply power-saving procedures, such as Discontinuous Reception (DRX), which may result in additional latency. Therefore, this paper aims to study the relationship between data freshness and power-saving performance. To capture the information freshness, we use Age of Information (AoI) as the performance metric. To the best of our knowledge, unlike previous studies that primarily focus on the trade-off between power saving and delay, this is the first study to consider the impact of DRX on the Age of Information (AoI). We have derived the closed-form solutions for both the peak-average AoI (PAoI) and time-average AoI (TAoI) under the DRX mechanism, along with their respective parameter adjustment strategies. Based on our simulation validation, these proposed strategies enable the UE to maintain the average AoI close to the theoretical lower bound while simultaneously achieving high power-saving efficiency. This positions our approach at the forefront of balancing information freshness and energy conservation in mobile and IoT networks.

In today's ever-growing data traffic landscape, optimizing network power efficiency and performance has become crucial. Discontinuous Reception (DRX) and Bandwidth Parts (BWP) are two key technologies that fulfill this pursuit. DRX is a time-domain power-saving technology that allows user equipment (UE) to switch off their radio frequency module. BWP switching is a frequency domain operation that allows UE to operate on only partial bandwidth for power saving. Investigating the interaction and trade-off between DRX and BWP is a must to optimize network efficiency and enhance network performance. This work proposed a novel BWP-DRX joint mechanism and its analytical model that leverages the concept of “Detect time” with the consideration of BWP switching delay. The model reduces packet loss rate by 50%, packet delay by 36% and increases the energy efficiency rate by 50% when arrival rate is high with the trade-off of 12% power efficiency reduction when arrival rate is low compared to the model without Detect time. The influence of each parameter is further analyzed to reach the best network efficiency under different traffic conditions.

In recent years, massive IoT networks have become increasingly important for achieving the 6G vision. However, the need for wireless resources for network management also increases, raising the importance of Multicast and Broadcast Services (MBS). With the natural constraint of the battery life of mobile devices, the Third Generation Partnership Project (3GPP) designed the Discontinuous Reception (DRX) mechanism for MBS to improve power efficiency in NR. The additional DRX for MBS is designed to operate independently from the existing UE-specific DRX. In this work, we point out that the independent operation of MBS DRX could severely degrade the power-saving feature of the DRX mechanism. We propose a DRX configuration method called Offset and Length-Aligned Multi-PTM (OLAM-PTM) for mixed unicast-MBS transmission scenarios. The results show that an MBS UE could dormant more at the cost of a slight increase in resource usage and execution time at the gNB side with OLAM-PTM.

Bandwidth part (BWP) and discontinuous reception (DRX) are critical designs to help devices save power. Unlike DRX, a time-domain power-saving mechanism, the BWP is a frequency-domain mechanism newly proposed in the 3GPP NR system. The interaction between the two mechanisms needs investigation for performance optimization. Therefore, this work proposed a joint design for the BWP switching algorithm and analytical models. The simulation results showed that when the DRX cycle is 320 ms, and the packet arrival rate is 0.01/ms, our method improves 31.4% of packet delay or 19.5% of power consumption compared to the baselines. We also showed the range of the traffic arrival rate that a UE with both mechanisms configured is sensitive to the BWP switch strategy.

Reducing the power consumption of User Equipment (UE) has always been a crucial issue in communication systems. As a result, Discontinuous reception (DRX) is introduced in today's New Radio (NR) networks as a power-saving strategy. In addition, the variety of low latency applications in 6G makes the issue of maintaining data freshness increasingly important. This paper aims to study the relationship between freshness and power-saving. To capture the information freshness, we use Age of Information (AoI) as the performance metric. To our best knowledge, unlike previous studies focusing on power saving and delay trade-offs, this is the first study considering the impact of DRX on AoI. We solve the closed-form solution of the peak average AoI with the DRX mechanism. Moreover, we propose a parameters adjustment strategy. Based on the simulation validation, our proposed strategy can enable the UE to keep the AoI close to the theoretical lower bound AoI while achieving high power-saving efficiency.

This paper develops a resource allocation mechanism of cooperative multicast under the integrated satellite-terrestrial network (ISTN). In cooperative multicast, base stations (BS) form different single frequency networks (SFN), and BSs within each SFN transmit data to mobile users (MU) with the same frequency, thus increasing signal intensity. Under this system architecture, we leverage the bottleneck user problem to characterize the overall system performance, where the bottleneck user is the MU with the lowest data rate inside each SFN. As the bottleneck user has poor signal strength, an SFN suffers a decrease in its Quality of Experience (QoE) provided to all users. Such an issue is alleviated under the ISTN: Users with poor signal strength can connect to the satellite that transmits with a moderate data rate, while the other users in the terrestrial network are unleashed from being grouped with them. In this regard, we propose an SFN-partitioning mechanism with the user-satellite association. In particular, our algorithm employs concepts from cooperative game theory and ensures Nash stability of the system. Finally, the simulation results validate the efficiency of the proposed mechanism.

The beamforming technique is applied in 5G NR systems to enhance the receiving signal power, especially for millimeter-wave communications. Beamforming complicates the paging procedure and brings extra overhead to the transmission of paging messages. In order to cover the serving area, the gNB should transmit broadcast control messages via beam sweeping. However, beam sweeping is inefficient for paging operation. In this work, an intelligent directional paging framework is proposed. The proposed beam-based paging list enables the gNB to page UEs flexibly. With the implicit gathering of the UE information, the gNB can make intelligent paging decisions without beam sweeping, decrease the paging resources consumption, and optimize the system paging delay. The proposed Markov chain based analytical model is validated by the simulation results. The results show that the proposed schemes outperform the NR baseline in successful paging rate, delay, and system capacity.

Discontinuous reception (DRX) is the most critical solution for user equipment (UE) power saving in mobile communications. Inspired by the wake-up radio (WUR) design in IEEE 802.11ba, the 3rd Generation Partnership Project (3GPP) standardized the Downlink Control information of Power saving (DCP) for the DRX mechanism. In this paper, we follow the DCP mechanism in 3GPP standard and derive the quantitative performance models for UE sleep ratio and delay. The proposed model is completely validated by the simulation results. In addition, we investigate the effects of DCP upon DRX mechanism. We also provided the relation between the latency distribution and DRX/DCP configurations. Our work benefits the extension and the improvement of the DCP mechanism.

In cellular networks, inter-cell interference is the main factor in the reduction of service quality for users, so intercell interference coordination (ICIC) has been widely studied to mitigate severe interference. However, in some previous work, cell- edge users are sacrificed to improve the performance of the overall system. Apart from this, most previous methods change the ICIC configuration frequently to achieve the optimal results, but in practice, the frequent ICIC reconfiguration results in large overhead for small cells. Thus, a centralized dynamic ICIC scheme is proposed in this work, including Q-learning assisted deep neural network based ICIC framework and Type-Balanced User Grouping algorithm. The simulation results show that the proposed ICIC scheme outperforms the benchmarks in both sparse and dense user distribution.

The development of indoor small cell provides network operators with new opportunities to address surging mobile data traffic, coverage infill and capacity boost scenarios, and finally results in growing expectations relative to quality of experience (QoE). However, the deployment of indoor small cell base station also raises some resource allocation issues. This study aims to propose an max‐utility resource allocation mechanism that maximises all users’ utility for indoor small cell networks. The objective of the proposed max‐utility resource allocation algorithm is to optimise the total user's QoE while guaranteeing as many as possible users can enjoy their request service at an acceptable quality. This is achieved by considering user's QoE state and signal strength into the resource allocation algorithm. Multiservice scenario is also considered in the proposed max‐utility resource allocation algorithm. To compare the performance of the proposed max‐utility resource allocation mechanism with round‐robin, max‐throughput and max‐minMOS approach, a simulation analysis is implemented. The simulation result showed that the proposed strategy achieves the best average utility compared with other approaches. Result also showed that the proposed strategy is suitable for indoor small cell networks under various kinds of scenarios with different user behaviours and network topologies.

Device-to-device (D2D) communications is an emerging service model that is currently under standardization by 3GPP. While D2D offloading has a great potential to relieve increasingly congested cellular networks, its benefits, however, come at a cost, namely interference. Most of the prevailing D2D designs conservatively avoid interference via either spectrum resource allocation or power control. These designs, however, do not exploit spatial degrees of freedom (DoF), which are inherently supported by multi-antenna devices. In this work, we present$\sf {MD2D}$, a multiuser D2D system that embraces concurrent D2D transmissions, while leveraging MIMO techniques to actively eliminate interference across D2D pairs.$\sf{MD2D}$has a systematic methodology that checks whether the antenna combination in a D2D network is capable of eliminating cross-pair interference and, thereby, ensuring interference-free concurrent transmissions. If the interference can be eliminated, then$\sf{MD2D}$applies abucket-based DoF assignment algorithmto determine an effective antenna usage configuration that handles the interference. We evaluate our design via testbed experiments and large-scale simulations. The results show that, as compared to the traditional interference avoidance scheme,$\sf{MD2D}$improves the throughput by 87.39 and 218.84 percent in a three-pair testbed and in large-scale simulations, respectively.