signal space

signal space is the linear-algebra sense space of possible signal vectors.

The basic idea is that every bit-message word \(m_0 \dots m_M\) can be uniquely mapped onto signals \(s_0(t) \dots s_M(t)\) where each value is a real energy signal defined on \([0, T)\).

For any set of these signals, we can represent it by a set of real orthonormal basis functions.