Integrated Sensing and Communications: Toward Dual-Functional Wireless Networks for 6G and Beyond

Wireless networks are the preferred future access networks for both defense and civilian deployments as part of telecommunication networks. The successful implementation of long term evolution (LTE) networks and applications such as the Internet of Things (IoT) in the telecommunication infrastructure has guaranteed rates of up to 100 Mbps while supporting ultra-dense wireless access network. With the incorporation of LTE-Advanced and fifth-generation wireless protocols, the data rates are expected to reach upto 1 Gbps. Hence, there is a pertinent requirement to carry out channel measurements at sub 1 GHz, 2 GHz, and 3 GHz bands to enable the design and implementation of optimum transceivers for pico-cells of LTE and future wireless networks. For the first time measurements and comparison with standard models of channel impulse response models have also been carried out in five different terrains namely Urban, Semi-Urban, Forest, Rural, and Desert terrains in the Indian sub-continent to effectively cover a variety of deployments of future wireless access networks for defense wireless networks

Green radios jointly consider the spectrum efficiency and the energy efficiency in wireless networks in order to provide sustainable development. In the past two decades, various green radio solutions for different types of terminals and radio access networks have been developed, some of which have been used in the designs of wireless products. In this paper, we provide a historical view on some fundamental works and practical issues. In addition to providing a comprehensive overview on theoretical achievements, we also discuss several important power saving solutions with notable engineering impacts, such as Doherty power amplifier and separated baseband unit - remote radio unit architecture, which might be overlooked in previous publications. Moreover, with the huge growth of wireless traffic in the near future, green radio design for future wireless networks shall involve an end-to-end energy efficiency investigation of mobile terminals, radio access and core networks, and different applications. By introducing green radio schemes for advanced terminals and future wireless networks, this article will not only be beneficial for readers with only preliminary background in communications and signal processing but also have reference and historical values for researchers and practical engineers in the area.

References

Multiple access methods in a wireless network allow multiple nodes to share a set of available channels for data transmission. The nodes can either compete or cooperate with each other to access the channel(s) so that either an individual or a group objective can be achieved. Game theory, which is a mathematical tool developed to understand the interaction among rational entities, can be applied to model and to analyze individual or group behaviour of nodes for multiple access in wireless networks. Game theory also enables us to model the selfish/malicious behaviour of nodes, and subsequently design the punishment or defense mechanisms for robust multiple access in wireless networks. In addition, game models can provide distributed solutions to the multiple access problems, which are based on solid theoretical foundations. In this survey, we provide a comprehensive review of the game models (e.g., noncooperative/cooperative, static/dynamic, and complete/incomplete information) developed for different multiple access schemes (i.e., contention-free and contention-based random channel access) in wireless networks. We consider time-division multiple access (TDMA), frequency-division multiple access (FDMA), and code-division multiple access (CDMA), ALOHA, and carrier sense multiple access (CSMA)-based wireless networks. In addition, game models for multiple access in dynamic spectrum access-based cognitive radio networks are reviewed. The major findings from the game models used for these different access schemes are highlighted. To this end, several of the key open research directions are outlined.

3G and beyond wireless networks will support user mobility fully based on mobile IP and provide multimedia services like video-conferencing etc. Although the outstanding service will be the real time service, the best effort service class will still remain as a basic service for Web browsing and short message services. Current Internet mostly relies on the TCP sliding window and slow start to regulate the source data rate and prevent congestion in the network. This paper describes network level congestion control based on explicit congestion notification (ECN) and introduces the future wireless network architecture. Also, wireless network traffic problems are introduced with numerical results and computer simulations, which shows the throughput improvement and increase of network stability when the proposed method is adapted in future wireless networks.

The emerging future heterogeneous wireless networks intend to provide a variety of adaptable services to mobile and nomadic users by using integrated heterogeneous network infrastructure. These networks are envisioned as the integration of different existing wireless network technologies such as WLAN, WiMAX, 2G, 2.5G, 3G, Bluetooth, etc., and future wireless network technologies. To integrate different network into a single heterogeneous network, the mobile station/user equipment (MS/UE) must discover all the available radio access networks ahead of time, select the appropriate network from the available radio access networks (RANs) and then seamlessly hand over the session to the desired/chosen network. This research paper presents a novel hybrid approach for network discovery, where the network will broadcast the updated network information using cell broadcast center (CBC) to the MS/UE and the MS/UE may also enquire from the network the additional information regarding the available networks, as opposed to centralized technique used in the existing cellular networks. The proposed solution suggests a network information repository (NIR) embedded in the core network, having the information of all the available radio access networks (RANs) in a specific location. The NIR will be populated and updated by the reporting agents (RAs) which are normal MS/UEs

In today’s technology, the essential property for wireless communication network is to exhibit as a dependable network. The dependability network incorporates the property like availability, reliability and survivability. Although these factors are well taken care by protocol for wired network, still there exists huge lack of efficacy for wireless network. Further, the wireless access network is more complicated with difficulties like frequencies allocation, quality of services, user requests. Adding to it, the wireless access network is severely vulnerable to link and node failures. Therefore, the survivability in wireless access network is very important factor to be considered will performing wireless network designing. This paper focuses on discussion of survivability in wireless access network. Capability of a wireless access network to perform its dedicated accessibility services even in case of infrastructure failure is known as survivability. Given available capacity, connectivity and reliability the survivable problem in hierarchical network is to minimize the overall connection cost for multiple requests. The various failure scenario of wireless access network as existing in literature is been explored. The existing survivability models for access network like shared link, multi homing, overlay network, sonnet ring, and multimodal devices are discussed in detail here. Further comparison between various existing survivability solutions is also tabulated.

In recent years, there has been a dramatic increase in the number of users who access online videos from wireless access networks. It is highly desirable that such wireless networks be robust in handling sudden spurts in demand for certain videos due to occurrences like special events. An abrupt increase in network usage should not significantly impact normal access to other regular videos or other day-to-day applications in a well-designed system. In this paper, we tackle this problem in wireless mesh access networks by proposing a distributed video sharing technique called Dynamic Stream Merging for Access Networks (DSMAN). DSMAN improves the robustness of the access network without requiring directives from the video servers. In fact, it optimizes the video transport independent of video server participation/knowledge. We present a wireless mesh network prototype based on DSMAN. Our experimental results, based on the mobile YouTube website as the video source, validate the correctness of DSMAN and demonstrate the feasibility of the proposed technique.

With more devices and emerging data-intensive services, mobile data traffic grows explosively, which makes the energy efficiency issue in current and future wireless networks be a growing concern. Recently, the advantages of bringing caching scheme in wireless networks have been widely investigated. Although additional power consumption is incurred by deploying caching equipments, the traffic loading balance of radio access network (RAN) and total network delay will be improved. In this paper, we study the energy efficiency problem in future wireless network. Particularly, we give an energy-delay tradeoff algorithm by using the sleeping control and power matching scheme. In the proposed algorithm, we consider a N-based sleeping control scheme, where the base station (BS) is in the sleep state whenever there is no arriving user, and works again when N users arrive. Moreover, the proposed algorithm is suitable for multi-BS scenario; to simplify the analysis, we mainly consider the single case. Simulation results shows that the proposed algorithm can obviously reduce the network power and delay in heterogeneous network conditions. Moreover, we find that a larger cache size does not always obtain a less network cost, because more cache power is consumed as cache size increases.

Wireless networking is approaching a new era. Existing wireless networks are usually implemented primarily for voice-type continuous traffic. However, due to the wide application of mobile computing devices, wireless packet networks will become a common scenario in future integrated service networks, as third generation wireless networks primarily support both voice and data applications. This situation makes an long-existing problem, that of multiple access, especially important in future wireless packet networks. This paper summarizes a series of studies on this subject and tries to reach a conclusion to fill the gap between information theoretic studies and practical protocol designs from the proposed universal view of multiple/random access protocols.

th -8 th 2007, in Jeju Island, Korea. It is our pleasure to organize eight workshops in conjunction with the main conference. The workshops are much focused and provide timely dissemination of latest research and high quality scholarly work. The workshops aim to explore special topics and provide open forums for scientists, engineers, and computer users to present, discuss and exchange state-of-the-art ideas on future generation communication and networking. The workshops are as follows: The 2nd International Symposium on Smart Home (SH'07); 2007 International Workshop on Cooperative Wireless Communications and Networking (CoNET-07); 2007 International Workshop on Peer-to-Peer Computing for Information Search (P2PSearch 2007); 2007 International Workshop on Future Broadband Wireless Access Systems, Communications, and Networks (FuBWA-07); 2007 International Workshop on Wireless Ad Hoc, Mesh and Sensor Networks (WAMSNet-07); The 2007 International Workshop on Forensics for Future Generation Communication Environments (F2GC-07); Communication & Network Technology Management 2007 (CNM 2007); Information Assurance in Networks 2007 (IAN 2007). SH07 fosters the dissemination of state-of-the-art research in the area of Smart Home Environments including business models, security services, and novel applications associated with its utilization. CoNET-07 brings together researchers to present new results and describe work in progress at the area of cooperative wireless communications and networking. P2PSearch 2007 presents the papers that facilitate better understanding of challenges of P2P information search with novel ideas, new techniques and innovative solutions. FuBWA-07 captures current and innovative ideas to highly active broadband wireless access area. WAMSNet-07 is intended to provide a high-quality forum for researchers and practitioners to present their latest theoretical and practical work in wireless ad hoc, mesh and sensor networks. F2GC-07 provides an opportunity for academic and industry professionals to discuss the latest issues and progress in the area of forensics for Future Generation Communication environments. CNM 2007 provides a chance to discuss recent technical progress in the area of Communication and Networking for academic and industry professionals and technical manager of organizations. IAN 2007 provides recent technical progress in the area of networks assurance for academic and industry professionals.

Recently, wireless networks are utilized in various situations. However, the characteristic of wireless environment causes many problems like limited bandwidth, collisions and interferences among transferred frames. It is required to enhance bandwidth with efficient channel utilization. In this paper, in wireless access networks where a base station and wireless stations communicate directly, we achieve higher network bandwidth by introducing multi-channel environment and utilizing each channel efficiently. Though wireless networking with multiple channels is well explored, the most of the related works focus on wireless multihop networks. However, the topology of wireless access networks we assume is completely different from multihop networks. Hence, a new multi-channel protocol, with different architecture and algorithm, is required to increase network bandwidth. In this paper, we propose a new protocol suited to the target environment. Specifically, the proposed method controls operation channel of each wireless station to minimize collisions and interferences caused by hidden station problem, and to balance data transfer load on every channel. Moreover, the proposed method minimizes the number of utilized channels by suppressing redundant usage of channels according to total data transfer load. This alleviates channel interferences among neighboring wireless access networks and restricts power consumption at base station. Finally, we show the effectiveness of the proposed method by computer simulation.

In the era of Industry 5.0, future wireless networks are increasingly shifting from traditional symmetric architectures toward heterogeneous and asymmetric paradigms, driven by the demand for diversified and dynamic services. This architectural evolution gives rise to complex and asymmetric flows, such as the coexistence of periodic and burst flows with varying latency, jitter, and deadline constraints, posing new challenges for deterministic transmission. Traditional time-sensitive networking (TSN) is well-suited for periodic flows but lacks the flexibility to effectively handle dynamic, asymmetric traffi. To address this limitation, we propose a two-stage asymmetric flow scheduling framework with dynamic deadline control, termed A-TSN. In the first stage, we design a Deep Q-Network-based Dynamic Injection Time Slot algorithm (DQN-DITS) to optimize slot allocation for periodic flows under varying network loads. In the second stage, we introduce the Dynamic Deadline Online (DDO) scheduling algorithm, which enables real-time scheduling for asymmetric flows while satisfying flow deadlines and capacity constraints. Simulation results demonstrate that our approach significantly reduces end-to-end latency, improves scheduling efficiency, and enhances adaptability to high-volume asymmetric traffic, offering a scalable solution for future deterministic wireless networks.

Future wireless cellular networks will utilize millimeter-wave and sub-THz frequencies and deploy small-cell base stations to achieve data rates on the order of hundreds of gigabits per second per user. The move to sub-THz frequencies will require attention to sustainability and reduction of power whenever possible to reduce the carbon footprint while maintaining adequate battery life for the massive number of resource-constrained devices to be deployed. This article analyzes power consumption of future wireless networks using a new metric, a figure of merit called the power waste factor ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$W$</tex> ), which shows promise for the study and development of “green G” - green technology for future wireless networks. Using <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$W$</tex> , power efficiency can be considered by quantifying the power wasted by all devices on a signal path in a cascade. We then show that the consumption efficiency factor (CEF), defined as the ratio of the maximum data rate achieved to the total power consumed, is a novel and powerful measure of power efficiency which shows that less energy per bit is expended as the cell size shrinks and carrier frequency and channel bandwidth increase. Our findings offer a standard approach to calculating and comparing power consumption and energy efficiency.

In order to meet the growing mobile data demand, future wireless networks will be equipped with a multitude of access points (APs). Besides the important implications for the energy consumption, the trend towards densification requires the development of decentralized and sustainable radio resource management techniques. It is critically important to understand how the distribution of signal processing operations affects the energy efficiency of wireless networks. In this paper, we provide a cross-layer framework to evaluate and compare the energy efficiency of wireless networks under different levels of distribution of the signal processing load: (i) hybrid, where the signal processing operations are shared between nodes and APs, (ii) centralized, where signal processing is entirely implemented at the APs, and (iii) fully distributed, where all operations are performed by the nodes. We find that in practical wireless networks, hybrid signal processing exhibits a significant energy efficiency gain over both centralized and fully distributed approaches.