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In-Flight Entertainment System
Rides the VMEbus
Todd Wynia, Heurikon Corp.
Today's in-flight entertainment packages encompass a lot more than a bag of peanuts, a movie and a cellular phone. Now, passengers can have interactive access to live broadcast TV, movies on demand, computer games, home shopping, and even gambling. BE Aerospace's VMEbus-based MDDS (Multimedia Digital Distribution System) does all that and more. And it does it with a centralized, redundant architecture that simultaneously enhances capacity, reduces cost, and boosts reliability.
Conventional in-flight entertainment systems use a distributed architecture in which multimedia content (such as games and movies) is stored centrally, but the decode intelligence (such as PCs and Nintendo players) is stored under the passenger's seat. The equivalent of placing a PC under each seat, this approach is expensive and bulky, adding a lot of weight to the plane. The under-the-seat approach also generates a lot of heat.
The MDDS solves this problem simply by using a cluster of centrally located VMEbus servers to store and decode content for all of the passenger seats. Decoded content is distributed to each passenger seat group as standard NTSC video signals. Each passenger is equipped with an LCD seatback display and hand-held interactive remote control. Basic rate ISDN (Integrated Services Digital Network) is used to carry telephone voice/data and key pad control information.
The MDDS currently provides four basic kinds of servers; an IBM PC server, a Nintendo server, a multitasking server, and an audio/video-on-demand server. All four servers are VMEbus based, output NTSC video (for transmission to passenger seats), and are linked with each other and other MDDS switching and control systems via Ethernet.
The Nintendo server supports 48 Nintendo players, with four Nintendo players implemented on each VMEbus card (up to twelve cards per server).
The IBM PC server contains 48 Intel 486-based PCs, each with up to 8 Mbytes of memory. PC services include games, gambling, shopping and transactional processing. Four PCs are implemented on each VMEbus card (a total of sixteen cards).
The Multitasking server is a SPARCStation with a 1-Gbyte hard disk, 64 Mbytes of memory and 140 NTSC outputs (320 x 240) with 256 colors. It provides menus, information screens, and support for transaction processing.
The Audio/Video-on-demand server (up to seven) stores and plays MPEG-encoded movies. Each server consists of three boxes: one is a file system that provides up to 34 Gbytes of storage for MPEG-encoded content (enough for 45 hours of video and 70 hours of 64-channel audio in 16 languages); the second box is a decoder array (32 MPEG decoders) that decodes MPEG audio and video streams that it receives from the file system in real time; The third box provides overall control for the server.
The MDDS' Entertainment Switching Unit (ESU) provides switching facilities that link the output of each server element (i.e., a particular movie, Nintendo player or PC) with each passenger seat. The MDDS' Communications Control Unit (CCU) provides the networking infrastructure that carries data and control information to and from the MDDS system, passengers and the outside world (i.e., for live broadcasts and cellular service). Ethernet is used to interconnect MDDS components such as the servers, CCU, and ESU. Basic Rate ISDN lines are used to connect the MDDS with passenger seat groups. A pair of E1 lines (the industry standard for airlines - the European version of a T1) link MDDS with the outside world.
Basic Rate ISDN (BRI) was chosen for its ability to carry audio (including telephony traffic), data (such as credit card swipes), and control information. BRI's two 64 kbit/sec B channels enables it to support bidirectional audio and data. At the same time, BRI's D channel provides 16 kbit/sec of bandwidth that can be used to carry control information and data.
Heurikon's Nitro VMEbus CPU boards act as traffic cops and high- speed data movers in the Nintendo, PC and audio/video-on-demand servers. Based on Motorola's MC68060 CPU, the Nitro boards decode and route incoming communications requests to the appropriate server element. They also move data to and from the server file systems and the decoders. Each Nitro board is equipped with Ethernet and SCSI-II interfaces, 16 Mbytes of DRAM, four Mbytes of flash memory, 512 kbytes of ROM, and two high-speed serial ports.
Thanks to BE Aerospace and Heurikon, flying isn't just for sleeping anymore. In fact, it might even take a call to security to get you to deplane at the end of your next flight.
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