I am doing my UG project on "optimized packet radio" in SDR. Presently, I am using costas loop block but i think it's recovering only the frequency of local oscillator but not the phase. Please correct me if i am wrong. Now the problem is i dont want to use dqpsk because it would cause a 3dB loss of power to attain the same BER which would kill the aim of optimization. So please give me some solution for "phase recovery" so that i can use simple qpsk without differential coding. Thank you.