We focus on the Age of Information (AoI) performance in a system where each user generates packets periodically to send to a common access point (AP) for status updating. To avoid heavy overhead, we assume that channel sensing, feedback information from the AP, and time synchronization are not available in the system. We adopt a multi-access scheme called the sequence scheme, where each user is assigned a periodic binary sequence to schedule their transmissions. In our previous work, we have thoroughly studied the AoI performance under the sequence scheme when the sequence period,L, is equal to the status generating period,T. However, the case ofT̸=Lis not covered by the previous work. Therefore, in this paper, we aim at analyzing the AoI performance for general values ofTandL, which is more challenging and requires different approaches. We conduct in-depth analysis and develop a mathematical tool based on integer partitions to facilitate the analysis. We derive low-complexity closed-form expressions for two special cases. Based on the obtained analytical results, we propose an optimization method for parameter selection in sequence construction to minimize the average AoI. Finally, we compare our proposed sequence scheme with two commonly used baselines, and show that our proposed scheme outperforms the baselines in terms of AoI performance while consuming less energy.

This paper focuses on protocol sequences for age of information (AoI) in a multiple-packet reception (MPR) channel without feedback and synchronization. Unlike traditional probabilistic schemes, protocol-sequences-based schemes allow each user to deterministically decide when to transmit only according to its assigned sequence. When the MPR capability$\gamma=2$, we use a previously known construction to generate user-irrepressible (UI) sequences that are favorable for the AoI improvement. Under this construction, by studying the reverse Hamming cross-correlations of the corresponding sequences, which is more complicated than that in prior studies, we provide an analytical approach for evaluating the AoI for$\gamma=2$. When$\gamma > 2$, we also propose a new construction to produce UI sequences for the AoI improvement. Simulation results show that the proposed schemes outperform slotted ALOHA in terms of average AoI and worst-case AoI for various settings.

Ultra-wideband (UWB) technology, known for its precise distance measurement capabilities, is widely utilized in indoor localization and ranging applications. However, recent UWB systems that operate within dense and dynamic networks face challenges in real-time performance evaluation and experimental data collection, especially in infrastructure-less scenarios. To address this, we present a mobile UWB testbed, which consists of a scalable ranging system, a data collection pipeline, and a mesh-based control network. This testbed facilitates UWB-related research such as ranging protocol design, as well as implementing and evaluating applications such as social interaction analysis and contact tracing.

This paper considers a system in which multiple users send periodically generated status information to a common access point (AP) over a collision channel. To avoid high overhead, there is no time synchronization and no feedback information from the AP to indicate whether a transmission is successful or not. The performance metric that we focus on is the age-of-information (AoI), which represents the freshness of the status information received at the AP. For this model, we propose a sequence based MAC scheme in which each user is pre-assigned a periodic sequence to schedule transmissions. This scheme guarantees each user at least one successful packet transmission within a sequence period, in the absence of time synchronization and feedback information from the AP. To the best of our knowledge, this is the first study investigating AoI performance under a sequence based MAC scheme. We derive the closed-form expressions for average AoI, average peak AoI and average age penalty under the sequence based scheduling. Besides, we derive several critical properties of the sequences to optimize the AoI performance. Comparison results show that our proposed sequence scheme outperforms slotted ALOHA and framed ALOHA in various settings.

With the development of Internet of Things (IoT), wireless communication networks and Artificial Intelligence (AI), more and more real-time applications such as online games and autonomous driving have emerged. However, due to limited computing power and battery capacity, it has become increasingly difficult for local user devices to take on the full range of computing tasks under tight timing constraints. The emerging Mobile Edge Computing (MEC) technology is widely considered to be an important technology for achieving ultra-low latency. However, most of the existing work is focused on non-splittable computation tasks. In fact, data partitioning-oriented applications can be split into multiple subtasks for parallel processing. In this paper, we study the partial computation offloading of multiple detachable tasks in MEC networks, focusing on minimizing the total user device latency in the multi-MEC multi-user scenarios. Considering the dynamic partitioning of tasks, we adopt the barrel theory to construct a linear system of equations to find the optimal solutions and propose an approach for distributed computation offloading based on numerical methods. The simulation results show that the proposed algorithm can reduce the average user device latency by 31 % compared with the binary offloading method.

We consider a single-hop wireless sensor network in which each sensor node has an individual elastic data stream to transmit to each other node. We refer to this traffic pattern as unicast in this paper. The network has multiple slotted channels available for the data transmissions. To guarantee successful unicast within a bounded delay, we consider deterministic schemes that pre-assign each node a periodic schedule sequence to schedule transmitting and receiving at each time slot. The sequence period should be minimized since it upper bounds the unicast delay. We have investigated both synchronous TDMA sequences and asynchronous sequences. Since accurate time synchronization is difficult to achieve in sensor networks, we mainly present analysis and design for asynchronous sequences. In this paper, for a group-based channel assignment, we present a lower bound on the common period and propose a sequence construction method by which the period can achieve the same order as the lower bound. We also analyze optimal transmitting and receiving probabilities for two random schemes and compare their frequency utilization efficiency. Finally, unicast delay and energy consumption performance are compared by simulations.

We consider an ad hoc network in which each node has an individual data stream to unicast to each of its neighboring nodes. Since the nodes may start their communications at different times, there exist delay offsets among them. The values of delay offsets are assumed to be unknown due to a lack of cooperation among the nodes and the absence of a centralized coordination mechanism. For such a network, we propose a distributed transmission scheduling scheme that pre-assigns to each node a periodic schedule sequence. We show that there exist schedule sequence sets for any finite number of nodes to ensure that each node can transmit at least one packet to each other node within a period, for all possible delay offsets. In this paper, we analyze the lower bounds on the period length and propose sequence construction methods to approach the lower bounds, for both of the single channel model and the multi-channel model.