Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is a promising technique to handle impairments of multipath channel. Alternatively, one of its major drawbacks is drift in carrier frequency, called Carrier Frequency Offset (CFO). Due to CFO, Inter Carrier Interference (ICI) occurs and results in a large performance degradation. The study proposes a novel two stage CFO estimation and compensation technique based on Expectation and Maximization (EM) algorithm with an iterative scheme. Unlike other CFO estimation algorithm, in our proposed CFO estimator a search interval is computed in two stages, hence the estimated offset is more optimal. In the first stage, coarse CFO estimation is done whereas fine estimation is performed in the second stage. This two stage computation results in more accurate and faster convergent estimate. From the simulation results it is proved that the Bit Error Rate (BER) performance of proposed method is more close to ideal Cramer-Rao Lower Bound (CRLB) curve.
Background: Breast cancer is the most common invasive cancer in the woman and second leading cause of cancer death. Early detection of breast cancer by clinical assessment, and further radiological investigation and early treatment can reduce the morbidity and mortality in such patients. Aim: To evaluate usefulness of BIRADS grading of mammography, fine needle aspiration cytology. To study the Sensitivity and specificity of mammography, ultrasonography and fine needle aspiration cytology. Materials and Methods: It is a prospective study of patients who presented with breast lump in the department of general surgery in the duration of August 2018-December 2019. The primary outcome of the study was evaluated on the basis of clinical examination, investigations like mammogram and or ultrasound and fine needle aspiration cytology in that order. Results: The present study deals with the Clinocopathological and Radiological correlation of breast lesions. A total of 50 cases were studied. The youngest patient in this study was 19 yrs and the oldest was 80 years. The Triple Test components (Physical Examination, Mammogram & / or Ultrasound and Fine needle aspiration cytology) were categorized as benign, suspicious and malignant. Triple Test was considered concordant when all the three elements indicated benign or all the three indicated malignant results. Among the 50 cases which had Clinocopathological and radiological correlation, 38 had all benign results and 8 had all malignant results. The age group of 31-40 yrs showed maximum number of benign cases. All the palpable lesions of the breast occurring in the age group of 10-30 years were benign in this study. Majority of the lesions occurring in the age group of 61-80yrs were malignant. Conclusion: Triple test reliably guides evaluation of palpable breast masses. Patients with palpable breast lesions should be evaluated by physical examination, mammogram and/or USG and fine needle aspiration. Cystic masses are best evaluated by USG. When all the three components of TT are concordant i.e., either concordant benign or concordant malignant, it yields 100% diagnostic accuracy. Amongst the three components of TT, FNA has the highest sensitivity of 100%.In the non-concordant cases it is found that FNA was more sensitive. TTS has a high diagnostic accuracy when the lesions score a TTS of S 6 and T 4. However, a TTS of 5 has low predictive value and such cases require open biopsy for confirmation of the diagnosis. Sites of fine needle aspiration increases the diagnostic accuracy by reducing the false negative results.
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