While the gap is smaller, many rural areas still have no ICT connection

WiMAX: key points LOS range: 50km NLOS range: 8km Cost: Goal of $100 CPE (customer premise equipment) NLOS allows indoor CPE installation Standardization

Combining several techniques Subchannelization Directional antennas Diversity schemes Adaptive modulation –Flex to actual fading conditions, so don’t have to budget for worst-case Error correction Power control –Base station tells CPE how much transmit power is needed, so don’t need to budget for worst-case

Subscriber Units WiMAX subscriber units are available in both indoor and outdoor versions from several manufacturers. Self-install indoor units are convenient, but radio losses mean that the subscriber must be significantly closer to the WiMAX base station than with professionally installed external units. As such, indoor installed units require a much higher infrastructure investment as well as operational cost (site lease, backhaul, maintenance) due to the high number of base stations required to cover a given area. Indoor units are comparable in size to a cable modem or DSL modem. Outdoor units are roughly the size of a textbook, and their installation is comparable to a residential satellite dish. (from wikipedia.com)

How is different from MAC layer: scheduling vs contention Range: kilometers vs 100s of meters Spectrum Allocation/licensing Wikipedia.com

Namibia, N$500 = $72

VSAT Advantages Availability: VSAT services can be deployed anywhere having a clear view of the Clarke BeltClarke Belt Diversity: VSAT provides a wireless link completely independent of the local terrestrial/wireline infrastructure - especially important for backup or disaster recovery services Deployability: VSAT services can be deployed in hours or even minutes (with auto-acquisition antennas) Homogenity: VSAT enables customers to get the same speeds and SLAs at all locations across their entire network regardless of location Acceleration: Most modern VSAT systems use onboard acceleration of protocols such as TCP ("spoofing" of acknowledgement packets) and HTTP (pre-fetching of recognized HTTP objects); this delivers high-quality Internet performance regardless of latency (see below) Multicast: Most current VSAT systems use a broadcast download scheme (such as DVB-S) which enables them to deliver the same content to tens or thousands of locations simultaneously at no additional costDVB-S Security: Corporate-grade VSAT networks are private layer-2 networks over the air Wikipedia.com

VSAT disadvantages Latency: Since they relay signals off a satellite in geosynchronous orbit 22,300 miles above the Earth, VSAT links are subject to a minimum latency of approximately 500 milliseconds round-trip. This makes them a poor choice for "chatty" protocols or applications such as online gaming Encryption: The acceleration schemes used by most VSAT systems rely upon the ability to see a packet's source/destination and contents; packets encrypted via VPN defeat this acceleration and perform slower than other network traffic Environmental concerns: VSATs are subject to signal attenuation due to weather ("rain fade"); the effect is typically far less than that experienced by one-way TV systems (such as DirecTV or DISH Network) that use smaller dishes, but is still a function of antenna size and transmitter power and frequency bandDirecTVDISH Network Installation: VSAT services require an outdoor antenna installation with a clear view of the southern sky; this makes installation in skyscraper urban environments or locations where a customer does not have "roof rights" problematic Wikipedia.com

VSAT training Fees for participants based in Nigeria: NGN per person. NGN per person for two per company. NGN per person for three to nine people per company. ($1 = NGN 132, NGN50000 = $410) Fees for International Participants (participants attending from outside Nigeria): US$ 550 per person. US$ 530 per person for two per company. US$ 520 per person for three to nine people per company.

The satellite dish

minimum US$ per mbps per month for satellite SAT3: US$7,000 – US$15,000 (SAT3/WASC/SAFE Consortium is an international fibre that goes from Portugal to South Africa and out across the Indian Ocean to Asia) 582

Rural Satellite VSAT Market in Middle East and Africa 2002 : 7, : 60,000