Ultra low cost base station timing module

Adaptive high-accuracy timing module : algorithms and performance bounds

“…Both [16] and [17] used the same correction signal creation model and they can meet the CDMA base station timing requirements. However, algorithms developed from [16] and [17] assume the linear stability dependencies of oscillators which may not be true in most situations. This thesis is based on [17].…”

“…However, algorithms developed from [16] and [17] assume the linear stability dependencies of oscillators which may not be true in most situations. This thesis is based on [17]. The system concept and hardware structure of [17] are described in In this chapter, a useful adaptive OCXO drift correction algorithm and related system structure based on [17] are reviewed.…”

“…This thesis is based on [17]. The system concept and hardware structure of [17] are described in In this chapter, a useful adaptive OCXO drift correction algorithm and related system structure based on [17] are reviewed. Then the deficiencies of this algorithm are demonstrated.…”

“…In [16] and [17], a single oven crystal oscillator (OCXO) is used and the Batch Least Squares (BLS) fit algorithm is applied to compensate for the OCXO deficiencies to meet the CDMA and WiMAX base station timing module specification in holdover mode. Besides the low cost of the OCXO, the smaller power consumption and small size allow the timing module to be integrated onto the base station modem card.…”

“…The temperature is linear related to the frequency stability of the oscillator at the turnover point, so it can be assumed that a straight line fit is applied to the temperature and the correction signal. A Batch Least Squares (BLS) method is used to determine the coefficients of the straight line fit [17] [18] [19]. The ageing effect is not considered, so the OCXO model equation is:…”