Ku-mobile: satellite multimedia services for cars in the Ku-band

Satellite radio for vehicles is normally hampered by the problem of the shadowing of the line of sight between satellite and receiver. In this paper, a personalized radio concept is proposed as an alternative to the streaming approach used for traditional radio: instead of transmitting a number of distinct continuous streams, individual audio and multimedia files are broadcasted. The received files are stored in a large cache located in the receiver of each mobile terminal. There, the files are sequentially played from the cache to generate a service similar to traditional radio/entertainment programs. This assembled program may depends on some user settings and does depend on the available files, which in turn depend on the reception conditions of each individual user. A continuous connection between the satellite and each receiver is therefore no longer required. Instead, it is sufficient to ensure that enough new files to generate an attractive program are available in the cache. Therefore, the aim is to reach a sufficiently high update rate for the content of the cache. A failure in the transfer of an individual file has no impact on the audible quality, since the only effect is that this file cannot be used when assembling the program. Besides its robustness, this approach opens new possibilities in terms of enhanced services, like the capability to skip or repeat part of the radio program, and to easily integrate additional data services like e.g. road and weather maps distribution or generic html content. Furthermore, this approach can be combined with the usage of satellite systems with low link margins, which are already available, for instance in the Ku-band. This results in low infrastructure costs for the deployment of such a system, together with the availability of new, personalized attractive features. An overview about the dedicated communication system being developed to support the novel concept presented above, including the status of an end-to-end demonstrator, will be given.