This commit refactors the CPU-based channel model for improved reusability and extends it with single-precision floating-point support.
This serves as a performance and correctness baseline for the new CUDA implementation.
Key changes include:
- The original double-based multipath_channel function is refactored to remove hardcoded antenna dimensions from its signature. It now accepts dynamically sized arrays, making it more flexible for use in simulators like dlsim and ulsim.
- A new multipath_channel_float function is introduced to operate on float data types, matching the GPU's native format.
- A corresponding add_noise_float function is also added to complete the floating-point CPU pipeline.
- The new float-based functions are designed to work with an interleaved IQ sample format ([I, Q, I, Q]), which is more suitable for vectorized (SSE) and GPU processing.