동기화된 주파수도약 확산대역 다중접속 네트워크 시스템을 위한 간섭신호의 통계적인 모델링 및 성능 분석 연구
- 동기화된 주파수도약 확산대역 다중접속 네트워크 시스템을 위한 간섭신호의 통계적인 모델링 및 성능 분석 연구
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- In this thesis, we analyze the performance of synchronous fast frequencyhopping spread-spectrum multiple-access (FHSS-MA) networks using M-ary frequency shift keying (MFSK) modulation under Rayleigh fading. First, we analyze the performance of binary soft decision decoded, synchronous, fast FHSSMA networks with MFSK and noncoherent detection in Rayleigh fading channels. The joint probability density function (pdf) of the absolute values of the correlator outputs is derived to compute the bit interleaved coded modulation (BICM) channel capacity and evaluate the soft decision decoding performance of the binary 3GPP Turbo and convolutional codes. Results indicate that soft decision decoding based on the derived pdf drastically outperforms traditional decoders based on the Gaussian approximation of the effect of the multipleaccess interference (MAI). The sensitivity of the derived soft decision decoder to estimation errors in system parameters and the required computational complexities of the derived soft decision decoding metrics are also investigated.
We also analyze the performance of M-ary Turbo coded, synchronous, fast FHSS-MA networks with MFSK and noncoherent detection under Rayleigh fading channels based on the joint pdf of the absolute values of the correlator outputs. The coded modulation (CM) channel capacity along with the associated normalized network throughput are computed and the frame error rate (FER) performance of M-ary Turbo codes designed in  are evaluated. Numerical results show that M-ary coded FHSS-MA networks dramatically outperform binary coded FHSS-MA networks, resulting in excess of three-fold increase in the network capacity.
Finally, we analyze the performance of both binary and M-ary Turbo coded, synchronous, fast FHSS-MA networks using coherent MFSK and quadrature amplitude modulation (QAM) under Rayleigh fading channels. The joint pdf of the correlator outputs is derived to compute the BICM and CM channel capacity along with the associated normalized network throughput. We also evaluate the FER performance of practical binary 3GPP Turbo codes  and M-ary Turbo codes designed in . Numerical results show that M-ary Turbo coded FHSS-MA networks using coherent MFSK significantly outperform binary and
M-ary Turbo coded FHSS-MA networks using QAM. Moreover, for the cases using QAM and coherent MFSK, we observe that the derived maximum likelihood (ML) soft decision decoders are quite insensitive to estimation errors in system parameters such as the number of active users in the network and the received signal to noise ratio (SNR) which are required to compute the ML soft metric at the receiver.
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