Claims:We claim: 1. A method for start of frame (SOF) detection in a faded communication channel, the method comprising: receiving a plurality of signals as an input signal at a receiver; correlating the received signal with a known pattern header; estimating the correlation between the received data signal and the known header pattern of the data signal, wherein the addition and subtraction of the inphase and quadrature components of the received signal with respect to the value of the known header sequence; computing the correlation magnitude by squaring and adding the inphase and quadrature components of the correlation output using a threshold estimation method; applying fixed and dynamic thresholds on the estimated correlated values, wherein the fixed threshold is derived by the observation of the data and the dynamic threshold is calculated based on the incoming data samples; comparing the correlated magnitude value with fixed and dynamic threshold value to determine the start of the frame; ascertaining the detection of start of frame by eliminating the false detections using the knowledge of the frame length and earlier header positions; and stating valid start of frame when the correlation magnitude is greater than or equal to the dynamic and the fixed thresholds. 2. The method as claimed in claim 1, wherein the dynamic threshold is determined by adding N correlation magnitude values before and after the present correlation magnitude value leaving M adjacent correlation magnitude values on both sides of the present correlation magnitude value and subsequently dividing this sum by 2N and multiplying it by a constant k. 3. The method as claimed in claim 1, wherein the inphase component of the correlation with the known pattern header is determined from the inphase (Ir) and the quadrature phase component (Qr) values of the received signal includes few steps: subtraction of Qr from Ir, if the inphase and quadrature phase components of header bit are 1,1; addition of Ir and Qr, if the inphase and quadrature phase components of header bit are 1,-1; subtraction of Ir from Qr, if the inphase and quadrature phase components of header bit are -1,-1; and addition of Ir and Qr and negating this value, if the inphase and quadrature phase components of header bit are -1, 1. 4. The method as claimed in claim 1, wherein the quadrature phase component of the correlation with the known pattern header is determined from the inphase (Ir) and the quadrature phase component (Qr) values of the received signal includes few steps: addition of Ir and Qr, if the inphase and quadrature phase components of header bit are 1,1; subtraction of Ir from Qr, if the inphase and quadrature phase components of header bit are 1,-1; addition of Ir and Qr and negating this value, if the inphase and quadrature phase components of header bit are -1,-1; and subtraction of Qr from Ir, if the inphase and quadrature phase components of header bit are -1, 1. 5. The method for computing the inphase and quadrature component values of correlation as claimed in claims 3 and 4, wherein a 4:1 multiplexer is used to compute the values and the selection lines of 4:1 multiplexer are derived from the known header pattern sequentially. 6. The method as claimed in claim 1, wherein the inphase and quadrature phase components obtained for each header bit are added separately for the entire header length to determine the correlation of the input signal with the header and the square of these two values are added to determine the correlation magnitude. 7. The method as claimed in claim 1, wherein a fixed threshold is also used to avoid start of frame detection in the absence of the signal. 8. The method as claimed in claim 1, wherein the history of the position of earlier start of frames is used to ascertain the detection of start of frame. 9. The method as claimed in claim 1, wherein the correlation magnitude being greater than or equal to the dynamic and the fixed thresholds indicates the possibility of detection of header position. 10. The method for eliminating the false detections as mentioned in claim 8,wherein the detection of start of frame is ascertained when current correlation magnitude under investigation has satisfied the conditions laid down in claim 8and Q out of P (Q