How to create a C++ or C# dll file (for serial port communication) to use it in MATLAB (M-file)?

Dear programmers,

I want to develop a fast serial port ('COM' port) program to read and write data to COM port. Senor (Hokuyo URG-04LX LRF) connected to the COM port contains about 2000 characters for once. I have partially done it but less than 1Hz of speed. I want to improve it up to 9~10 Hz.

I'm looking for using dll file created using C++ or C# that can be directly used in MATLAB to read and write the data. I hope this will be faster than the direct use of MATLAB serial communication. If I'm wrong please make it correct.

I want to know how to generate a C++ or C# dll file step by step tutorial and how can I use it in MATLAB.

Any comment, suggestion or reference please.