Abstract: A universal method of trellis encoding signals mapped according to any signal constellation format involves constructing an encoder output table and a state transition table. The encoder output table defines the output symbol of an encoder given the input symbol and the present state of the encoder, while the state transition table defines the next state of the encoder given the present state of the encoder and the input applied to the encoder. The output table and the next state table are constructed with the objective of providing maximal distances between the branches of the trellis diagram without any regards for the shift register implementation of the code. Cyclic trellis-coded modulation is an example of such codes without feed-forward or feed-back shift register implementations, and with equal or better performance than “optimal” shift register trellis codes with 16 states or less.

Abstract: A bed assembly comprising a metal frame of generally rectangular configuration including a pair of opposed side rails and a pair of opposed end rails and a plurality of metal slats extending transversely between the side rails in spaced parallel relationship to one another and to the end rails. Both of the end and side rails have a hollow cross section along their respective lengths. The hollow cross section in each of the rails is defined at least by two metal members welded together. The end rails of a first embodiment and all of the rails of a second embodiment are defined by a pair of U-shaped members having their legs overlapping with the bases of the U shapes spaced from one another to define the hollow cross section. The side rails of the first embodiment are defined by channeled members having a channel extending therealong and a plate-like strip covering the channel to define the hollow cross section.