Single-Carrier Rate Adaptive Digital Subscriber Line (RADSL)
|Publication Date:||1 September 1999|
This technical report describes the interface between the telecommunication network and the customer installation in terms of their interaction and electrical characteristics using single-carrier modulation. The recommendations in this document apply to a Rate Adaptive Digital Subscriber Line (RADSL) system, which include Physical Media Dependent (PMD) sub-layer and Physical Transmission Convergence (PTC) sub-layer, and interfaces to higher layer entities.
Transmission from the network to the customer premises is referred to as the downstream channel and supports line rates up to approximately 8 Mbit/s. Transmission from the customer premises to the network is referred to as the upstream channel and supports line rates up to approximately 1 Mbit/s. Both the downstream and upstream channels are frequency division multiplexed (FDM) above the voice band analog channel.
The transmission system is designed to operate on single twisted metallic cable pairs with mixed gauges. The system is based on the use of cables without loading coils, but bridged taps are acceptable with the exception of unusual situations.
This technical report permits network providers an expanded use of existing copper facilities for the support of rate adaptive data applications and multimedia services. Physical medium dependent (PMD) sub-layer aspects, physical transmission convergence (PTC) sub-layer methods, and maintenance functions are described for both network equipment and equipment at the remote location.
Specifically, this document
- describes the transmission technique used to support the simultaneous transport of POTS and the upstream and downstream channels of the rate adaptive digital signals on a single twisted pair;
- describes the line modulation and the spectral composition of signals transmitted by both RADSL Transceiver Unit at the Central office (ATU-C) and that at the remote location (ATU-R);
- describes the receive signals at both the ATU-R and ATU-C;
- describes electrical and mechanical specifications of a network interface;
- describes a common logical interface to the ATM-TC, Packet-TC, Bit-Synchronous-TC and EOCTC sublayers;
- describes operation and maintenance communications over an Embedded Operations Channel (EOC);
- describes the exchange of information sequences during start-up to establish system configuration and transmission link; and
- describes performance objectives and test procedures.