Broadcom announced EchoStar Communications Corp. is using its 8PSK turbo code technology across EchoStar's new DISH Network DBS receivers. As direct-to-home satellite providers struggle to find the bandwidth to add additional services and more local stations, higher order modulation methods such as 8PSK are needed. However, while higher order modulation allows much higher data rates than simpler methods such as QPSK (Quadrature Phase Shift Keying), the carrier to noise ratio needed to decode the signal also increases, requiring more satellite power or larger receive dishes. Turbo code technology sacrifices some of the data bandwidth to add advanced forward error correction coding to the signal, providing a coding gain that allows successful operation with a reduced carrier to noise ratio.
Broadcom's 8PSK turbo code "increases information throughput by 35 percent in a given bandwidth or radio frequency link with no additional power requirements," according to the company. Mark Jackson, Senior Vice President of EchoStar Technologies Corporation commented, "Broadcom's turbo code technology enables us to deploy a field-proven solution meeting the technical performance that our service offering requires. We can provide our customers expanded services while continuing to provide them the variety and premium quality channels they have come to expect from DISH Network."
The Broadcom BCM4500 Advanced Modulation Satellite Receiver chip supports BPSK, QPSK and 8PSK modulation and includes the advanced modulation turbo-code forward error correction decoder. The BCM4500 can be combined with the BCM3440 Direct Conversion Satellite Tuner chip to make a complete DBS satellite receiver. More information and block diagrams are available in the PDF files in the above links.
