Learn More
—Many applications require fast data transfer over high speed and long distance networks. However, standard TCP fails to fully utilize the network capacity due to the limitation in its conservative congestion control (CC) algorithm. Some works have been proposed to improve the connection's throughput by adopting more aggressive loss-based CC algorithms.(More)
To meet the needs of wireless broadband access, the IEEE 802.16 protocol for wireless metropolitan networks (WirelessMAN) has been recently standardized. The medium access control (MAC) layer of the IEEE 802.16 has point-to-multipoint (PMP) mode and mesh mode. Previous works on the IEEE 802.16 have primarily focused on the PMP mode. In the mesh mode, all(More)
—Radio spectrum resource is of fundamental importance for wireless communication. Recent reports show that most available spectrum has been allocated. While some of the spectrum bands (e.g., unlicensed band, GSM band) have seen increasingly crowded usage, most of the other spectrum resources are underutilized. This drives the emergence of open spectrum and(More)
It has been a challenging problem to support VoIP-type delay sensitive applications in an 802.11 wireless LAN, because the standard handoff procedure implemented in many current 802.11 products occurs a delay deem unacceptable to VoIP users. To reduce this delay, we have developed a fast handoff scheme called Proactive Scan. It employs two new techniques.(More)
– Many applications require fast data transfer over high speed and long distance networks. However, standard TCP fails to fully utilize the network capacity in high-speed and long distance networks due to its conservative congestion control (CC) algorithm. Some works have been proposed to improve the connection's throughput by adopting more aggressive(More)
Broadband wireless access technology is developed very fast in recent years. The IEEE 802.16 and 802.11a are two broadband wireless access system standards for metropolitan and local areas respectively. The IEEE 802.11a works in the license-exempt (LE) band, and the IEEE 802.16 is designed such that it can operate in the same LE spectrum too. Although the(More)
As we are moving toward the next generation all-IP wireless networks, we are facing the integration of heterogeneous networks, such as WWAN and WLAN, where vertical handoff is required. In vertical handoff between WWAN and WLAN, mobile hosts should be able to move freely across different networks while satisfying QoS requirements for a variety of(More)
— Most of the real deployed peer-to-peer streaming systems adopt pull-based streaming protocol. In this paper, we demonstrate that, besides simplicity and robustness, with proper parameter settings, when the server bandwidth is above several times of the raw streaming rate, which is reasonable for practical live streaming system, simple pull-based P2P(More)
Dynamic spectrum access has been a subject of extensive research activity in recent years. The increasing volume of literature calls for a deeper understanding of the characteristics of current spectrum utilization. In this paper we present a detailed spectrum measurement study, with data collected in the 20MHz to 3GHz spectrum band and at four locations(More)