课程名称︰无线多媒体系统研究 课程性质︰多媒体 课程教师︰吴晓光 开课学院：电资 开课系所︰资工 考试日期（年月日）︰2010.01.14 考试时限（分钟）：180 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1. The Session Initiation Protocol (SIP) provides advanced signaling and control functionality for a wide variety of multimedia services. (A) Explain why and how SIP could support personal mobility. (B) Explain how caller could influence can influence the routing of the SIP message. (C) Explain how SIP could support forking function? (D) While almost all phone calls are between parties, signaling also would be required to accommodate multiparth calls (such as "Push to talk"). Describe how SIP could be enhanced to support multiparth calls. (E) Compare Mobile IP and SIP for mobility support. (F) Since SIP agent could also communicate with each other directly with each other, do you have suggestions for service provides (offering SIP services) for billing and security concerns? 2. 4G-cellular systems should not only be high speed but also high-capacity, with low bit cost and the ability to support the services of the 2010s. IEEE Standard 802.16-2001, completed in Octrober 2001 and published on 8 April 2002, defines the WirelessMan air interface specification for wireless metropolitan area networks (MANs). (A) Describe and illustrate the up-link scheduling services (based on those defined on cable modems in the DOCSIS standard). (B) Explain how IEEE 802.16 operates adaptive burst profiling in the radio link control. (C) Describe why IEEE 802.16 specifies two classes of SS. (D) Explain why in both TDD and FDD systems, the UL MAP might not be able to allocate starting in the current frame. 3. (A) Explain how IEEE 802.11 address the power conservation issue. (B) The EC- MAC (Energy Conserving-Medium Access Control) protocol, on the other hand, was developed with the issueof energy efficiency as a primary design goal. The EC_MAC protocol is defined for an infrastructure network with a single base station serving mobiles in its coverage area. Can you describe cases that EC-MAC perform better power conservation than IEEE 802.11 power saving? (C) Explain how PAMAS (Power Aware Multiple Access) potocol addresses the power conservation issue. 4. (a) Can you descirbe two main motications for the Terminal Project: Toward Self- Organized Mobile AdHoc Networks? (B) Can you describe Ad hoc network evolutions from early stage to the future? (C) Can you describe the characteristics of Ad hoc networks? (d) In the early stage, two kinds of routing schemes: (1) table driven routing scheme (such as DSDV) (2) on demand routing scheme (such as AODV). Can you explain the difference between them? (e) What are the similarities and differences between ad hoc networks and sensor networks? 5. (A) Explain why DS (Direct Sequence) waveforms can be used to either reject multipath returns that fall outside of the correlation interval of the spreading waveform, or enhance overall performance by diversity combining multipath returns in a TAKE receiver. (B) Explain why reverse link is vulnerable to the "near far" problem, and what is solution to maximize the system capacity?(C) Explain soft handoff and softer handoff?(D) How WCDMA could provide flexible services (Flexible bit rates) for different kind of users? 6. (A) Different from traditional routing schemes, recently, geographical methods have been utilized for routing. Can you describe how geographic information can be helpful for the routing schemes? (c) Can you explain the following example? (D) Usually real time service might require stringent delay constraint and not allow retransimission. How to provide real time service under an unpredictable environment? 7. The goal of Mobile IP is to allow a mobile host to send and receive packets addresses with its home address regardless of its current point of attachment to the internet. (A) Can you explain what are encapsulation and tunneling for mobile IP? (B) For security reason, some router will enforce to apple source address filtering. Then what is going to impact Mobile IP? (C) Do you have solution for the security limit in (B) (D) Explain what is the disadvantafe to adopt enhanced DNS approach to solve the mobility problem? (E) Describe why mobile IP adopts two-tier addressing. -- Nothing is Impossible --

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