外文翻譯：ad_hoc網(wǎng)絡(luò)的一個(gè)簡要概述：挑戰(zhàn)與研究方向(已修改)
2025-06-01 05:00 本頁面
【正文】 2 附 錄 一、 英文原文 A Brief Overview of ad hoc Networks: Challenges and Directions One of the most vibrant and active “new” fields today is that of ad hoc works. Significant research in this area has been ongoing for nearly 30 years, also under the names packet radio or multihop works. ad hoc work is a (possibly mobile) collection of munications devices (nodes) that wish to municate, but have no fixed infrastructure available, and have no predetermined organization of available links. Individual nodes are responsible for dynamically discovering which other nodes they can directly municate with. Ad hoc working is a multilayer problem. The physical layer must adapt to rapid changes in link characteristics. The multiple access control (MAC) layer needs to minimize collisions, allow fair access, and semireliably transport data over the shared wireless links in the presence of rapid changes and hidden or exposed terminals. The work layer needs to determine and distribute information used to calculate paths in a way that maintains efficiency when links change often and bandwidth is at a premium. It’s also needs to integrate smoothly with traditional, non ad hocaware interworks and perform functions such as autoconfiguration in this changing environment. The transport layer must be able to handle delay and packet loss statistics that are very different than wired works. Finally, applications need to be designed to handle frequent disconnection and reconnection with peer applications as well as widely varying delay and packet loss characteristics. Ad hoc works are suited for use in situations where infrastructure is either not available, not trusted, or should not be relied on in times of emergency. A few examples include: military solders in the field。 sensors scattered throughout a city for biological detection。 an infrastructureless work of notebook puters in a conference or campus setting。 the forestry or lumber industry。 rare animal tracking。 space exploration。 undersea operations。 and temporary offices such as campaign headquarters. History The history of ad hoc works can be traced back to 1972 and the DoDsponsored Packet Radio Network (PRNET), which evolved into the Survivable Adaptive Radio Networks(SURAN) program in the early 1980s [l]. The goal of these programs was to provide packetswitched working to mobile battlefield elements in an infrastructureless, hostile environment (soldiers, tanks, aircraft, etc., forming the 3 nodes in the work). In the early 1990s a spate of new developments signaled a new phase in ad hoc working. Notebook puters became popular, as did opensource software, and viable munications equipment based on RF and infrared. The idea of an infrstructureless collection of mobile hosts was proposed in two conference papers [2,3], and the IEEE submittee adopted the term “ad hoc works.” The concept of mercial (nonmilitary) ad hoc working had arrived. Other novel nonmilitary possibilities were suggested (as mentioned in the introduction), and interest grew. At around the same time, the DoD continued from where it left off, funding programs such as the Global Mobile Information Systems(GloMo), and the Nearterm Digital Radio(NTDR). The goal of GloMo was to provide officeenvironment Ethertype multimedia connectivity anytime, anywhere, in handheld devices. Channel access approaches were now in the CSMA/CA and TDMA molds, and several novel routing and topology control schemes were developed. The NTDR u
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