近年來，802.11無線網路已如雨後春筍般在世界的各個角落被使用，雖然無線網路的技術提高了使用者迅速上網的方便性，但802.11 MAC層卻無法滿足使用者在無線多媒體應用的需求。也因此，許多針對如何改善802.11 QoS的研究不斷地被提出，IEEE 802.11 也新增修訂了IEEE 802.11e。

在許許多多研究中，IEEE 802.15.3 (UWB)標準也提出了他們如何針對個人無線區域網路(WPAN)提供好的QoS，802.15.3的工作小組以低功率及更高的傳輸速率為前提，提出了一個更有效率的方式來滿足多媒體即時應用的需求。由於這樣的效能可能成為消費性電子產品的下一里程碑，UWB標準在一提出已獲得了許多廠商的目光。然而，相關的產品至目前為止仍然是非常的有限；另一方面，我們也尚未聽聞針對IEEE 802.15.3 MAC層的相關實驗。

因此，我們利用現有的802.11 WiFi 網路介面卡，將IEEE 802.15.3的superframe機制實現在其上層。我們利用UDP，高精密度計時器(HRT)，以及IEEE 802.11原本MAC的機制，CSMA/CA，並且選擇最佳的參數來達成superframe的功用。此外，我們也以superframe來測試VoIP的容量，使得每個VoIP的即時需求都達到最佳。在802.11b的MAC限制下，我們可得的最大VoIP容量為12通。然而，我們的實驗不但確認了IEEE 802.15.3 MAC的可行性，同樣也顯示出UWB的MAC機制確能提供極佳的QoS。

IEEE 802.11 WLAN deployments have been mushroomed into every corner of the world in the recent years. Although wireless technology has saved a lot of time and energy for the users, the original media access mechanism cannot satisfy the needs of wireless multimedia applications. Subsequently, researches are continually being proposed on improving QoS requirements.. IEEE 802.11 was also amended into IEEE 802.11e for the same reason.

In another area, IEEE 802.15.3 standards were also published to provide QoS for Wireless Person Area Networks. They attempt to provide a more efficient way to meet the multimedia requirement with low-power consumption and high data rates. The appearance of UWB standards has gained a lot of attention since it may be a new milestone for portable electronics consuming devices. However, relative products are still rarely seen in the present markets. Also, we haven’t seen relative experiments based on IEEE 802.15.3 MAC.

We implemented IEEE 802.15.3 superframe mechanism on the interface of IEEE 802.11. We utilized the UDP, High Resolution Timers, and the natural IEEE 802.11 CSMA/CA to achieve the superframe functions with considered parameters. Also, we simulated VoIP connections on our UWB system under the best real-time requirements. The maximum capacity is 12 calls under the limitation of IEEE 802.11b MAC. However, we have proved the feasibility of the IEEE 802.15.3 MAC and the fine QoS it supports.

[1] “Part 15.3: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specification for High Rate Wireless Personal Area Networks (WPAN),” IEEE Standard 802.15.3, September 2003.
[2] http://www.ieee802.org/15/pub/TG3.html
[3] James P. K. Glib, “Wireless Multimedia…A Guide to the IEEE 802.15.3 Standard,” IEEE, 2004.
[4] “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications”, IEEE standards, June 2003.
[5] http://en.wikipedia.org/wiki/Peer-to-peer
[6] Sachin Garg, Martin Kappes, "An Experimental Study of Throughput for UDP and VoIP Traffic in IEEE 802.11b Networks”
[7] K. Medepalli, P. Gopalakrishnan, D. Famolari, T. Kodama, “Voice Capacity of IEEE 802.11b, 802.11a, and 802.11g Wireless LANS”, IEEE Communication Society. Globecome 2004
[8] Sangho Shin, Henning Schulzrinne, “Experimental Measurement of the Capacity for VoIP Traffic in IEEE 802.11 WLANs”, 2007 IEEE
[9] “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements,” IEEE Standard 802.11e, November 2005.
[10] http://www.voip-info.org/wiki/view/QoS
[11] Sachin Garg, Martin Kappes, "Can I add a VoIP call?," Communications, 2003. ICC '03. IEEE International Conference
[12] http://www.connect802.com/
[13] Fanglu Guo, Tzi-cker Chiueh, “Software TDMA for VoIP Applications over IEEE802.11 Wireless LAN”, 2007 IEEE
[14] http://www.opengroup.org/rtforum/jan2002/slides/linux/mehaffey.pdf
[15] W. Richard Stevens, “UNIX Network Programming Volume 1”
[16] http://sourceforge.net/projects/high-res-timers
[17] http://sourceforge.net/projects/zd1211
[18] http://www.wildpackets.com/images/compendium/802dot11_frame.gif
[19] http://en.wikipedia.org/wiki/User_Datagram_Protocol