ofdmflexframesync: moving to BPSK header for improved reliability
ofdmflexframesync: moving to BPSK header for improved reliability

  * frame needs approximately 0.9dB SNR for 90% probability of decoding
  * improvement from about 2.0dB SNR requirement
  * doubles header length, unfortunately

manuts/liquid-dsp,biotrump/liquid-dsp,cjcliffe/liquid-dsp,andrepuschmann/liquid-dsp,JayKickliter/liquid-dsp,jgaeddert/liquid-dsp,andrepuschmann/liquid-dsp,biotrump/liquid-dsp,JayKickliter/liquid-dsp,manuts/liquid-dsp,manuts/liquid-dsp,biotrump/liquid-dsp,cjcliffe/liquid-dsp,JayKickliter/liquid-dsp,manuts/liquid-dsp,jgaeddert/liquid-dsp,manuts/liquid-dsp,cjcliffe/liquid-dsp,JayKickliter/liquid-dsp,jgaeddert/liquid-dsp,cjcliffe/liquid-dsp,andrepuschmann/liquid-dsp,wangning223/liquid-dsp,wangning223/liquid-dsp,cjcliffe/liquid-dsp,biotrump/liquid-dsp,wangning223/liquid-dsp,andrepuschmann/liquid-dsp,jgaeddert/liquid-dsp,jgaeddert/liquid-dsp,wangning223/liquid-dsp,JayKickliter/liquid-dsp,andrepuschmann/liquid-dsp,biotrump/liquid-dsp,wangning223/liquid-dsp