Abstract—Ultra-wideband (UWB) transmission is an emerging wireless communication technology with unique potential merits such as high-rate, low-transmission power, immunity to multipath propagation, and capability in precise positioning. It has received significant interests for future wireless communications from both academia and industry. In UWB wireless networks, medium access control (MAC) is essential to coordinate the channel access among competing devices. The unique UWB characteristics not only pose significant challenges but also offer great opportunities in efficient UWB MAC design. This paper presents a comprehensive overview of UWB MAC development on four important aspects: multiple access, overhead reduction, resource allocation, and quality of service (QoS) provisioning, and identifies some future research issues. Index Terms—Medium access control (MAC), quality of service (QoS), resource allocation, ultra-wideband (UWB) transmission, wireless personal area network (WPAN). I.

Abstract—Ultrawideband (UWB) communication is an emerging technology that promises to provide high data rate communication for wireless personal area networks. One of the critical challenges in UWB system design is the timing acquisition problem, i.e., a receiver needs a relative long time to synchronize with transmitted signals. Clearly, the timing acquisition overhead will significantly limit the throughput of high data rate UWB ad hoc networks. To resolve the timing acquisition problem, the authors proposed a general framework for medium access control (MAC) protocols in their previous work (K. Lu, D. Wu, and Y. Fang, “A novel framework for medium access control in ultra-wideband ad hoc networks, ” Dynamics of Continuous, Discrete and Impulsive Systems (Series B), vol. 12, no. 3, pp. 427–441, Jun. 2005); under the framework, a transmitting node can aggregate multiple upper layer packets into a burst frame at the MAC layer. In this paper, the authors propose an aggregation-based MAC protocol within the framework. Besides packet aggregation, they also design a novel retransmission scheme which is suitable for error-prone wireless environment, in which only the packets that encounter transmission errors will be retransmitted. To evaluate the performance of the protocol, they develop a three-dimensional Markov chain model for the saturated throughput performance. In addition, they also analyze the end-to-end delay performance through simulation. Extensive numerical and simulation results show that, compared to existing MAC protocols, in which upper layer packets are transmitted one by one, the proposed protocol can drastically reduce the timing acquisition overhead. Consequently, both the throughput and the end-to-end delay performance can be significantly improved. Index Terms—Bit error rate (BER), burst frame, delay, medium access control (MAC), throughput, timing acquisition, ultrawideband (UWB).

Abstract — In this paper, with a cross-layer design principle, we propose an interference aware distributed resource management scheme for a code-division multiple access (CDMA)-based wireless mesh backbone (consisting of a number of wireless routers at fixed sites). Specifically, benefiting from the fixed location of wireless routers, the power allocation is based on the length of the transmission path, so as to ensure a certain level of fairness among the routers. For a new call arrival, based on the maximum sustainable interference concept, each existing receiver (rather than the potential sender) estimates its experienced interference level under the hypothesis that the new call is admitted. If the interference is not tolerable, the existing receiver rejects the new call by sending a blocking-signal. The main advantages of our proposed scheme are the low control message overhead for easy implementation, and the accurate interference estimation. Simulation results are presented to evaluate the performance of our scheme. Index Terms — CDMA, cross-layer design, resource management, wireless mesh networks.

channel acquisition time of UWB is high, and a lot of packets are short in FCS. So the efficiency of FCS based on UWB will significantly reduce. In this paper, a CSMA/CA protocol with D-UF (Dynamic Length Mechanism for Unite Frame) is proposed. The characteristics of UWB and size of data packets in FCS are taken into account in the CSMA/CA protocol with D-UF. First, the characteristics of UWB and FCS are discussed, and the slot utilization of CSMA/CA protocol is analyzed in different FCS. Finally, the packet assembly policy is designed. At the same time, the performance of the CSMA/CA protocol with D-UF is evaluated in FCS based on UWB by modeling and simulation. Simulation results show that the CSMA/CA protocol with D-UF is effective to increase slot utilization, and improve throughput, and reduce average delay in the FCS based on UWB. It is useful to engineer for designing the FCS based on UWB. Index Terms—dynamic length, FCS, UWB, CSMA/CA example, the UWB is used for ground penetrating radar. This characteristic makes the UWB have greater potential for industrial automation applications than exciting other technology. Some bandwidth types are showed in Table I.

Abstract — Quality of service (QoS) provisioning is one of the most important criteria in newly emerging UWB-operated WPANs, as they are expected to support a wide variety of applications from time-constrained, multimedia streaming to throughput-hungry, content transfer applications. As such, the Enhanced Distributed Coordinated Access (EDCA) mechanism has been adopted by MultiBand OFDM Alliance in its UWB MAC proposal. In this paper, we conduct a rigorous, comprehensive, theoretical analysis and show that with the currently recommended parameter setting, EDCA cannot provide adequate QoS. In particular, without responding to the system dynamics (e.g., taking into account of the number of active class-i stations), EDCA cannot allocate bandwidth in a deterministic proportional manner and the system bandwidth is under-utilized. After identifying the deficiency of EDCA, we propose, in compliance with the EDCA-incorporated UWB MAC protocol proposed in [18] [23] [24], a framework, along with a set of theoretically grounded methods for controlling medium access with deterministic QoS for UWB networks. We show that in this framework, 1) real-time traffic is guaranteed of deterministic bandwidth via a contention-based reservation access method; 2) best-effort traffic is provided with deterministic proportional QoS; and moreover, 3) the bandwidth utilization is maximized. We have also validated and evaluated the QoS provisioning capability and practicality of the proposed MAC framework both via simulation and empirically by leveraging the MADWifi (Multiband Atheros Driver for WiFi) Linux driver for Wireless LAN devices with the Atheros chipset. I.

Abstract — In recent years, UWB has received much attention as a suitable Physical Layer (PHY) for Wireless Personal Area Networks (WPANS). UWB allows for low cost, low power, high bandwidth, short reach communication well suited for personal operating spaces. One of the key features offered by UWB is very accurate ranging between a transmitter/receiver pair. The IEEE 802.15.3 is a MAC protocol that has been proposed for WPANs. In this MAC, a combination of CSMA/CA and TDMA is used to achieve channel scheduling. The TDMA component ensures only one transmitter/receiver pair within a piconet is active at any given time thereby ensuring an exclusion region that covers the whole piconet. In this paper, we propose a less stringent scheduling mechanism that allows for concurrent communication between UWB transmitter/receiver pairs within a piconet. Exclusion is necessary only when the communicating entities are close enough such that interference between them would adversely affect successful reception of data at the receivers. The Piconet Coordinator (PNC) uses the ranging information provided by UWB to accurately position transmitters and receivers. The PNC schedules parallel transmissions between distinct transmit/receive pairs as long as they do not interfere. We present the results of our simulations of our proposed modifications and show that the network throughput can be significantly increased with very little change to the 802.15.3 MAC. I.

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The purpose of this thesis is the implementation and evaluation of a MAC Layer in a network simulator for the research in the Ultra Wide Band eld. Ultra Wide Band is a technology consisting in the transmission of very short pulses which allow the communications with a very low power consumption at high data rates and without interfering other existing systems. This technology is based on techniques of Impulse Radio transmissions used in the radar eld and therefore has strong penetrating and high resolution position location capabilities. These properties make the UWB signal a good solution for many different applications. It is appropriated for Wireless Personal Area and Sensor Networks, since the devices in these scenarios are supposed to work with limited batteries. Principally, networking protocols for UWB networks are in many ways similar to those appro-priate for other wireless networks. However, since the design of an efcient MAC often requires an accurate knowledge of the physical layer, the particular characteristics of the UWB physical channel motivate some changes, especially in the data link layer (LLC and MAC). In the case of UWB systems, the cross-layer design paradigm is a crucial issue due to the particular potentials and challenges of UWB technology, e.g. the precise ranging capability, or the difculties in per-