tailieunhanh - Điện thoại di động giao thức viễn thông cho các mạng dữ liệu P3

Wireless local area networks Virtual LANs provide support for workgroups that share the same servers and other resources over the network. A flexible broadcast scope for workgroups is based on Layer 3 (network). This solution uses multicast addressing, mobility support, and the Dynamic Host Configuration Protocol (DHCP) for the IP. The hosts in the network are connected to routers via point-to-point connections. The features used are included in the IPv6 (Internet Protocol version 6) protocol stacks. Security can be achieved by using authentication and encryption mechanisms for the IP | Mobile Telecommunications Protocols For Data Networks. Anna Hac Copyright 2003 John Wiley Sons Ltd. ISBN 0-470-85056-6 3 Wireless local area networks Virtual LANs provide support for workgroups that share the same servers and other resources over the network. A flexible broadcast scope for workgroups is based on Layer 3 network . This solution uses multicast addressing mobility support and the Dynamic Host Configuration Protocol DHCP for the IP. The hosts in the network are connected to routers via point-to-point connections. The features used are included in the IPv6 Internet Protocol version 6 protocol stacks. Security can be achieved by using authentication and encryption mechanisms for the IP. Flexible broadcast can be achieved through enhancements to the IPv6 protocol stack and a DHCP extension for workgroups. Orthogonal Frequency Division Multiplex OFDM is based on a mathematical concept called Fast Fourier Transform FFT which allows individual channels to maintain their orthogonality or distance to adjacent channels. This technique allows data symbols to be reliably extracted and multiple subchannels to overlap in the frequency domain for increased spectral efficiency. The IEEE standards group chose OFDM modulation for wireless LANs operating at bit rates up to 54 Mb s-1 at 5 GHz. Wideband Code Division Multiple Access WCDMA uses 5 MHz channels and supports circuit and packet data access at 384 kb s-1 nominal data rates for macrocellular wireless access. WCDMA provides simultaneous voice and data services. WCDMA is the radio interface technology for Universal Mobile Telecommunications System UMTS networks. Dynamic Packet Assignment DPA is based on properties of an OFDM physical layer. DPA reassigns transmission resources on a packet-by-packet basis using high-speed receiver measurements. OFDM has orthogonal subchannels well defined in time-frequency grids and has the ability to rapidly measure interference or path loss parameters in parallel on all .