wireless ATM links

In this paper we investigate the influence of buer,management for TCP on performance of the High Speed Downlink Channel (HS-DSCH) introduced in WCDMA release 5. HS-DSCH is a shared channel, but user data is buered,individually prior to the wireless link. Three queue man- agement principles, e.g., passive queuing, the Packet Discard Prevention Counter (PDPC) method,and the Random Early Detection

Mesh networks are candidate to play the role of switched Ethernet LANs over extended areas and with a sensibly higher flexibility. Actually, mesh networks can exploit both Ethernet and wireless technologies, e.g. Wi-Fi and/or free-space optical links, to provide a high degree of redundancy in an access network, and to provide users with powerful means to connect with each other.

With the widespread growth of applications of Wireless Sensor Networks (WSNs), the need for reliable security mechanisms these networks has increased manifold. Many security solutions have been proposed in the domain of WSN so far. These solutions are usually based on well-known cryptographic algorithms. In this paper, we have made an effort to survey well known security issues in WSNs and study the behavior of WSN nodes that perform public key cryptographic operations. We evaluate time and power consumption of public key cryptography algorithm for signature and key management by simulation. Keywords—Wireless Sensor Networks, Security, Public Key Cryptography, Key Management.

The adoption of wireless sensor networks by applications that require complex operations, ranging from health care to industrial monitoring, has brought forward a new challenge of fulfilling the quality of service (QoS) requirements of these applications. However, providing QoS support is a challenging issue due to highly resource constrained nature of sensor nodes, unreliable wireless links and harsh operation environments.

Mobile ad hoc networks (MANETs) are a set of mobile nodes which are self-configuring and connected by wireless links automatically as per the defined routing protocol. The absence of a central management agency or a fixed infrastructure is a key feature of MANETs. These nodes communicate with each other by interchange of packets, which for those nodes not in wireless range goes hop by hop. Due to lack of a defined central authority, securitizing the routing process becomes a challenging task thereby leaving MANETs vulnerable to attacks, which results in deterioration in the performance characteristics as well as raises a serious question mark about the reliability of such networks. In this paper we have attempted to present an overview of the routing protocols, the known routing attacks and the proposed countermeasures to these attacks in various works.

A feature-rich second-generation 60-GHz transceiver chipset is introduced. It integrates dual-conversion superheterodyne receiver and transmitter chains, a sub-integer frequency synthesizer, full programmability from a digital interface, modulator and demodulator circuits to support analog modulations (e.g. MSK, BPSK), as well as a universal I&Q interface for digital modulation formats (e.g. OFDM). Achieved performance includes 6-dB receiver noise figure and 12 dBm transmitter output ldB compression point. Wireless link experiments with different modulation formats for 2-Gb/s real-time uncompressed HDTV transmission are discussed. Additionally, recent millimeter-wave package and antenna developments are summarized and a 60GHz silicon micromachined antenna is presented.

Internet-enabled wireless devices continue to proliferate and are expected to surpass tradition-al Internet clients in the near future. This has opened up exciting new opportunities in the mobile e-commerce market. However, data secu-rity and privacy remain major ...

Due to the advent of the Internet, electronic business transactions have exploded around the globe. Along with the Internet, wireless technology has exponentially developed as well. Today, new technologies that allow mobile (cellular) phones and other handheld devices to access the Internet have made wireless business transactions possible. This phenomenon is known as mobile commerce or M-Commerce. It has been predicted that the number of mobile phones connected to the mobile Internet will exceed the number of Internet-connected PCs before 2007. The mobile phone will therefore become the most prevalent device for accessing the Internet. Several industry analysts predict that Mcommerce will constitute a multibillion dollar business by 2005. However, M-Commerce brings new challenges in providing information security as information travels through multiple networks often across wireless links. What must be done to secure financial transactions via mobile commerce? Generally speaking, M...

Internet enabled wireless devices continue to proliferate and are expected to surpass traditional Internet clients in the near future. This has opened up exciting new opportunities in the mobile e-commerce market. However, data security and privacy remain major concerns in the current generation of "wireless Web" offerings. All such offerings today use a security architecture that lacks end-to-end security. This unfortunate choice is driven by perceived inadequacies of standard Internet security protocols like SSL (secure sockets layer) on less capable CPUs and low-bandwidth wireless links. This paper presents our experiences in implementing and using standard security mechanisms and protocols on small wireless devices. Our results show that SSL is a practical solution for ensuring end-to-end security of wireless Internet transactions even within todays technological constraints.

In 802.11 wireless links with disabled MAC retries, data and ACK packets within a TCP session collide resulting in packet losses. We show in this paper that in this situation, certain popular optimizations of TCP (fast-recovery) worsen the performance by causing ...

A complete 3.1-10.6 GHz ultra-wide band receiver using 500 MHz-wide sub-banded binary phase shift keyed (BPSK) pulses has been specified, designed and integrated as a three chip and planar antenna solution. The system includes a custom designed 3.1-10.6 GHz planar antenna, direct-conversion RF front-end, 500 MS/s analog to digital converters, and a parallelized digital back-end for signal detection and demodulation. A 100 Mb/s wireless link has been established with this chipset. A bit-error-rate (BER) of 10-3 was recorded at -80 dBm at a rate of 100 Mb/s for properly acquired packets in the lowest frequency band. Bit-scaling of the ADC from 1 to 5 bits reveals a 4 dB improvement in the link budget