Synchronization apparatus for a diversity receiver

A diversity combiner for use with a receiver for receiving a plurality of wireless transmitted electromagnetic signals, said receiver having associated signal processing means for generating a plurality of complex baseband signals (S.sub.1 (t), S.sub.2 (t)), from said plurality of wireless transmitted electromagnetic signals, said diversity combiner comprising:

• means for differently detecting each of said complex baseband signals (S.sub.1 (t), S.sub.2 (t)) to produce a plurality of differential signals (RX.sub.1 (t), RX.sub.2 (t)), in accordance with
• RX.sub.1 (t)=S.sub.1 (t).multidot.S.sub.1 *(t-T), and
• RX.sub.2 (t)=S.sub.2 (t).multidot.S.sub.2 *(t-T)
• where S.sub.x * is the complex conjugate of S.sub.x and T is a symbol delay;
• means for generating a selected differential signal R(t) from said differential signals (RX.sub.1 (t), RX.sub.2 (t));
• means for converting said selected differential signal R(t) to produce a plurality of converted signals D.sub.1 (t) and D.sub.2 (t) in according with
• D.sub.1 (t)=R(t).multidot.e.sup.-j2.pi.fst
• D.sub.2 (t)=R(t).multidot.e.sup.+j2.pi.fst
• where fs is the sub-harmonic frequency, t=nTs, where Ts is the sampling period, and n is determined by the periodicity of:
• fs*nTs=1;
• or n=1/(fs*Ts);
• and
• means for processing said converted signals D.sub.1 (t) and D.sub.2 (t) to produce timing (.tau.) and frequency (f.sub.e) error estimate signals by:
• ##EQU8## where C.sub.1 (t) and C.sub.-1 (t) are the averages of D.sub.1 (t) and D.sub.2 (t) respectively.

A telecommunication receiver for receiving a wireless transmitted electromagnetic signal, said receiver comprising:

• antenna means for receiving said wireless transmitted electromagnetic signals and for converting same to a plurality of radio frequency (RF) signals;
• means for converting said plurality of RF signals into a plurality of intermediate frequency (IF) signals each having an amplitude and for limiting the amplitude of each IF signal and for generating a receive signal strength intensity (RSSI) signal associated with each IF signal;
• bandpass converting means for receiving said plurality of IF signals and for producing a plurality of complex baseband signals (S.sub.1 (t), S.sub.2 (t)), one associated with each IF signal;
• diversity combiner means for receiving said plurality of complex baseband signals (S.sub.1 (t), S.sub.2 (t), said diversity combiner means comprising:
• means for differentially detecting each of said complex baseband signals (S.sub.1 (t), S.sub.2 (t)) to produce a plurality of differential signals (RX.sub.1 (t), RX.sub.2 (t)), in accordance with
• RX.sub.1 (t)=S.sub.1 (t).multidot.S.sub.1 *(t-T),and
• RX.sub.2 (t)=S.sub.2 (t).multidot.S.sub.2 *(t-T)
• where S.sub.x * is the complex conjugate of S.sub.x and T is a symbol delay;
• means for generating a selected differential signal R(t) from said differential signals (RX.sub.1 (t), RX.sub.2 (t));
• means for converting said selected differential signal R(t) to produce a plurality of converted signals D.sub.1 (t) and D.sub.2 (t) in according with
• D.sub.1 (t)=R(t).multidot.e.sup.-j2.pi.fst
• D.sub.2 (t)=R(t).multidot.e.sup.+j2.pi.fst
• where fs is the sub-harmonic frequency, t=nTs, where Ts is the sampling period, and n is determined by the periodicity of:
• fs*nTs=1;
• or n=1/(fs*Ts);
• means for processing said converted signals D.sub.1 (t) and D.sub.2 (t) to produce timing (.tau.) and frequency (f.sub.e) error estimates by:
• ##EQU10## where C.sub.1 (t) and C.sub.-1 (t) are the averages of D.sub.1 (t) and D.sub.2 (t) respectively;
• and
• means for receiving said timing (.tau.) and frequency (f.sub.e) error estimate signals and for detecting symbols in said selected differential signal R(t).