Telecommunications and New technologies.

the ground wave used for radio communications signal propagation on the long, and medium wave bands for local radio communications Ground wave propagation is particularly important on the LF and MF portion of the radio spectrum. Ground wave radio propagation is used to provide relatively local radio communications coverage, especially by radio broadcast stations that require to cover a particular locality. Ground wave radio signal propagation is ideal for relatively short distance propagation on these frequencies during the daytime. Sky-wave ionospheric propagation is not possible during the day because of the attenuation of the signals on these frequencies caused by the D region in the ionosphere. In view of this, radio communications stations need to rely on the ground-wave propagation to achieve their coverage. A ground wave radio signal is made up from a number of constituents. If the antennas are in the line of sight then there will be a direct wave as well a...

[WiMax - 802.16d/e] WiMAX is a term coined to describe standard, interoperable implementations of IEEE 802.16 wireless networks, in a rather similar way to Wi-Fi being interoperable implementations of the IEEE 802.11 Wireless LAN standard. However, WiMAX is very different from Wi-Fi in the way it works. In Wi-Fi, the media access controller ("MAC") uses contention access - all subscriber stations that wish to pass data through a wireless access point ("AP") are competing for the AP's attention on a random interrupt basis. This can cause distant nodes from the AP to be repeatedly interrupted by closer nodes, greatly reducing their throughput. This makes services such as Voice over IP (VoIP) or IPTV, which depend on a predetermined type of "quality of service" (QoS), difficult to maintain for large numbers of users. In contrast, the 802.16 MAC uses a scheduling algorithm, where the subscriber station only has to compete once (for initial en...

[MSAN] A Multi Service Access Node (MSAN) is a device typically installed in a telephone exchange (although sometimes in a roadside serving area interface cabinet) which connects customers' telephone lines to the core network, to provide telephony, ISDN, and broadband such as DSL all from a single platform. Prior to the deployment of MSANs, telecom providers typically had a multitude of separate equipment including DSLAMs to provide the various types of services to customers. Integrating all services on a single node, which typically backhauls all data streams over IP or Asynchronous Transfer Mode can be more cost effective and may more quickly provide new services to customers. Typical outdoor MSAN cabinet consists of NarrowBand (POTS), BroadBand (xDSL) services, batteries with rectifiers, optical transmission unit and copper distribution frame. [DSLAM] A Digital Subscriber Line Access Multiplexer (DSLAM) allows telephone lines to make faster connections to t...

[IPTV] IPTV (Internet Protocol Television) is a system where a digital television service is delivered using Internet Protocol over a network infrastructure, which may include delivery by a broadband connection. A general definition of IPTV is television content that, instead of being delivered through traditional broadcast and cable formats, is received by the viewer through the technologies used for computer networks. For residential users, IPTV is often provided in conjunction with Video on Demand and may be bundled with Internet services such as Web access and VoIP. The commercial bundling of IPTV, VoIP and Internet access is referred to as "Triple Play" service (adding mobility is called "Quadruple Play"). IPTV is typically supplied by a service provider using a closed network infrastructure. This closed network approach is in competition with the delivery of TV content over the public Internet, called Internet Television. In businesses, I...