Yau Kho | Nazarbayev University (original) (raw)
Papers by Yau Kho
2021 IEEE International Conference on Engineering, Technology & Education (TALE)
receiver incorporating channel estimation and tracking for a frequency selective fading environme... more receiver incorporating channel estimation and tracking for a frequency selective fading environment is developed. It employs near-maximum likelihood sequence estimation using the parti-tioned Viterbi algorithm and offers linearly increasing complexity with the number of transmit antennas. The receiver implements channel estimation and tracking using a vector-polynomial-based generalized recursive least squares algorithm. The resulting in-tegrated receiver can operate in a continuously time-varying Rayleigh or Rician fading environment. Simulation results show that it offers a good tradeoff between complexity and performance. Further complexity reduction can be achieved using tentative decisions as reference signals to the estimator and a reduced complexity form of the estimator. Index Terms—Channel estimation, equalizers, fading channels, mobile communication, multiple-input–multiple-output (MIMO) systems. I.
2019 IEEE International Conference on Engineering, Technology and Education (TALE), 2019
Good and effective communication skills, in Global Competence Understanding global markets and bu... more Good and effective communication skills, in Global Competence Understanding global markets and business particular for technical and scientific writing in English, is practices: languages; work in multicultural important for engineering students who need to have good global environments; global ethics, safety and security; cultural, social and political whose first language is English. Generally, poor writing is also evident in the test statistics of the International English Language Testing System (IELTS) where writing has consistently the lowest score band among four test categories, even for those whom English is the first language. Intrigued by this phenomenon, we analyzed the writing of final year technical knowledge as well as competent soft skills. This is awareness increasingly being demanded by professional accreditation bodies. In response, institutions of higher education nowadays have courses or programs that teach students the soft skills part of these requirements, wi...
2016 IEEE 10th International Conference on Application of Information and Communication Technologies (AICT), 2016
The problems faced by most senior citizens living alone at homes along with their poor health con... more The problems faced by most senior citizens living alone at homes along with their poor health conditions have motivated the development of a home monitoring system which aims at improving their wellness and health-care. The purpose of this system is to monitor the physiological parameters in real time, together with the help from a computer vision module. Several research works on this area have been conducted, however, the combination of image processing and wearable sensors have not been widely reported. The daily activities and health parameters are to be further analyzed. In case of any abnormal or emergency situations, alarm will be triggered and urgent message will be sent to a medical doctor.
This thesis looks at the problem of channel estimation and equalization in a multiple-input multi... more This thesis looks at the problem of channel estimation and equalization in a multiple-input multiple-output (MIMO) dispersive fading environments. Two classes of MIMO receiver structure are proposed with integrated channel estimation and tracking. One is a symbol-by-symbol based receiver using a MIMO minimum mean square error (MMSE) decision feedback equalizer (DFE), and the other is a sequence-based receiver using a partitioned Viterbi algorithm (PVA) which approaches the performance of maximum likelihood sequence estimation (MLSE). A MIMO channel estimator capable of tracking the time and frequency selective channel impulse responses, known as the vector generalized recursive least squares (VGRLS) algorithm, is developed. It has comparable performance and a similar level of complexity as the optimum Kalman filter. However, it does not require any knowledge of the channel statistics to operate and as such it can be employed in a Rician fading channel readily. A reduced complexity f...
In this paper, non-orthogonal multiple access (NOMA) with successive interference cancellation (S... more In this paper, non-orthogonal multiple access (NOMA) with successive interference cancellation (SIC) technique for downlink channel of next generation wireless network and its security issues are discussed. In NOMA, signals for all user equipment (UEs) are superimposed before transmission and then decoded at each UE implementing SIC. SIC relies on decoding and subtracting the signals in sequence until it reaches its desired signal. The decoding order at each UE, however, must match with the user index in the cancellation sequence. In case of mismatch, UEs will not obtain their signals and re-request their messages from the BS which will further increase the processing time that is already high for a regular SIC receiver. Numerical results show the performance of SIC at the UE side. The time spent for decoding the received signal at the UE with and without user mismatch is discussed. The unusual longer decoding times are further discussed as potential external network threat.
Capstone project (CP) is an integral part of an undergraduate engineering degree. It is important... more Capstone project (CP) is an integral part of an undergraduate engineering degree. It is important because it gives students the opportunity to demonstrate the breadth of knowledge and skills that they have learnt in the whole of their undergraduate courses. It is therefore critical to have a well-defined and well-designed CP as a concluding part to a Bachelor degree engineering program especially in demonstrating that students and the program fulfil the accreditation requirements of relevant accreditation bodies. In this paper, we discuss how these CP assessment tasks can be conducted such that they can be mapped to most of the 42 points within the 6 broad categories of the Engineering Council UK (ECUK) graduate competencies requirements.
With the abundance of ubiquitous transmission of wireless signals nowadays due to the proliferati... more With the abundance of ubiquitous transmission of wireless signals nowadays due to the proliferation of wireless devices, these man-made radio frequency signals in the form of electromagnetic waves can be exploited in various forms, for example localization and tracking. Here, we describe how these signals can be used in sensing an object or human in the environment. We describe the design concept and implementation of an indoor passive tracking system that utilises an array of Wi-Fi transceivers, and without any electronic device or tag attached to the object being tracked. The sensing of an object or a person described here is made possible by exploiting the fundamental characteristic of signal attenuation due to blocking, i.e. shadowing, that is prevalent in a typical wireless communication system. By detecting significant signal attenuation in the system (i.e. by measuring the received signal strength value), it is possible to infer that an object is blocking the line-of-sight (L...
2018 International Conference on Computing and Network Communications (CoCoNet)
Non-orthogonal multiple access (NOMA) is a promising method for the fifth generation (5G) cellula... more Non-orthogonal multiple access (NOMA) is a promising method for the fifth generation (5G) cellular networks as it provides improved spectral efficiency by multiplexing users in power domain. One key challenge for the receivers in NOMA networks is to distinguish the individual signals that use the same band at the same time. Currently, the two widely discussed decoding schemes are successive interference cancellation (SIC) and parallel interference cancellation (PIC). Both schemes suppress the multi-user interference by subtracting the decoded signals from the received signal based on different algorithms, i.e., SIC decodes iteratively and PIC decodes collectively. This paper compares the computation time of SIC and PIC schemes at the base station and demonstrates multi-thread implementation of PIC.
This paper presents a Generalized Power Allocation (GPA) scheme for different users in Non-Orthog... more This paper presents a Generalized Power Allocation (GPA) scheme for different users in Non-Orthogonal Multiple Access (NOMA) based wireless communication system. The power allocation to the users becomes complex with the increased number of users. There are some conventional schemes for power allocation in NOMA but they have to optimize some parameters arbitrarily. In this paper, a simple but effective power allocation scheme has been formulated and tested by simulations. The proposed GPA scheme does not need any parameter adjustment. Theoretical power distribution to different users of NOMA has been calculated using the proposed GPA technique. The calculated powers of individual users with the proposed scheme are different and more distributed than the arbitrary power allocation scheme which satisfies the basic condition of NOMA. The total of calculated powers with GPA scheme shows only 01% variation with the arbitrary power allocation scheme which shows the consistency of GPA scheme with other schemes. The performance of NOMA based wireless communication system with GPA scheme has been simulated under various conditions using Matlab. The simulated BER performance for NOMA based wireless communication system using different modulation techniques show similar results with other conventional schemes which validates the formulation of GPA scheme.
This thesis looks at the problem of channel estimation and equalization in a multiple-input multi... more This thesis looks at the problem of channel estimation and equalization in a multiple-input multiple-output (MIMO) dispersive fading environments. Two classes of MIMO receiver structure are proposed with integrated channel estimation and tracking. One is a symbol-by-symbol based receiver using a MIMO minimum mean square error (MMSE) decision feedback equalizer (DFE), and the other is a sequence-based receiver using a partitioned Viterbi algorithm (PVA) which approaches the performance of maximum likelihood sequence estimation (MLSE). A MIMO channel estimator capable of tracking the time and frequency selective channel impulse responses, known as the vector generalized recursive least squares (VGRLS) algorithm, is developed. It has comparable performance and a similar level of complexity as the optimum Kalman filter. However, it does not require any knowledge of the channel statistics to operate and as such it can be employed in a Rician fading channel readily. A reduced complexity f...
TENCON 2009 - 2009 IEEE Region 10 Conference, 2009
ABSTRACT The error rate performance of a previously developed reduced complexity channel estimato... more ABSTRACT The error rate performance of a previously developed reduced complexity channel estimator, known as the generalized least mean squares (GLMS) algorithm, is investigated in conjunction with a minimum-mean-square-error (MMSE) decision feedback equalizer (DFE). The channel estimator is based on the theory of polynomial prediction and Taylor series expansion of the underlying channel model in time domain. It is a simplification of a previously developed generalized recursive least squares (GRLS) estimator, achieved by replacing the online recursive computation of the `intermediate' matrix by an offline pre-computed matrix. Similar to the GRLS estimator, it is able to operate in Rayleigh or Rician fading environment without reconfiguration of the state transition matrix to accommodate the non-random mean components. Simulation results show that it is able to offer a trade-off between reduced complexity channel estimation and good system performance.
IET 2nd International Conference on Wireless, Mobile and Multimedia Networks (ICWMMN 2008), 2008
ABSTRACT The error rate performance of a previously developed reduced complexity channel estimato... more ABSTRACT The error rate performance of a previously developed reduced complexity channel estimator, known as the generalized least mean squares (GLMS) algorithm, is investigated in conjunction with a minimum-mean-square-error (MMSE) decision feedback equalizer (DFE). The channel estimator is based on the theory of polynomial prediction and Taylor series expansion of the underlying channel model in time domain. It is a simplification of the generalized recursive least squares (GRLS) estimator, achieved by replacing the online recursive computation of the ‘intermediate’ matrix by an offline pre-computed matrix. Similar to the GRLS estimator, it is able to operate in Rayleigh or Rician fading environment without reconfiguration of the state transition matrix to accommodate the non-random mean components. Simulation results show that it is able to offer a trade-off between reduced complexity channel estimation and good system performance.
2015 9th International Conference on Sensing Technology (ICST), 2015
Ieee Transactions on Vehicular Technology, Feb 1, 2009
A sequence-based multiple-input-multiple-output receiver incorporating channel estimation and tra... more A sequence-based multiple-input-multiple-output receiver incorporating channel estimation and tracking for a frequency selective fading environment is developed. It employs near-maximum likelihood sequence estimation using the partitioned Viterbi algorithm and offers linearly increasing complexity with the number of transmit antennas. The receiver implements channel estimation and tracking using a vector-polynomial-based generalized recursive least squares algorithm. The resulting integrated receiver can operate in a continuously time-varying Rayleigh or Rician fading environment. Simulation results show that it offers a good tradeoff between complexity and performance. Further complexity reduction can be achieved using tentative decisions as reference signals to the estimator and a reduced complexity form of the estimator.
2015 9th International Conference on Sensing Technology (ICST), 2015
2015 International Conference on Computer, Communications, and Control Technology (I4CT), 2015
2021 IEEE International Conference on Engineering, Technology & Education (TALE)
receiver incorporating channel estimation and tracking for a frequency selective fading environme... more receiver incorporating channel estimation and tracking for a frequency selective fading environment is developed. It employs near-maximum likelihood sequence estimation using the parti-tioned Viterbi algorithm and offers linearly increasing complexity with the number of transmit antennas. The receiver implements channel estimation and tracking using a vector-polynomial-based generalized recursive least squares algorithm. The resulting in-tegrated receiver can operate in a continuously time-varying Rayleigh or Rician fading environment. Simulation results show that it offers a good tradeoff between complexity and performance. Further complexity reduction can be achieved using tentative decisions as reference signals to the estimator and a reduced complexity form of the estimator. Index Terms—Channel estimation, equalizers, fading channels, mobile communication, multiple-input–multiple-output (MIMO) systems. I.
2019 IEEE International Conference on Engineering, Technology and Education (TALE), 2019
Good and effective communication skills, in Global Competence Understanding global markets and bu... more Good and effective communication skills, in Global Competence Understanding global markets and business particular for technical and scientific writing in English, is practices: languages; work in multicultural important for engineering students who need to have good global environments; global ethics, safety and security; cultural, social and political whose first language is English. Generally, poor writing is also evident in the test statistics of the International English Language Testing System (IELTS) where writing has consistently the lowest score band among four test categories, even for those whom English is the first language. Intrigued by this phenomenon, we analyzed the writing of final year technical knowledge as well as competent soft skills. This is awareness increasingly being demanded by professional accreditation bodies. In response, institutions of higher education nowadays have courses or programs that teach students the soft skills part of these requirements, wi...
2016 IEEE 10th International Conference on Application of Information and Communication Technologies (AICT), 2016
The problems faced by most senior citizens living alone at homes along with their poor health con... more The problems faced by most senior citizens living alone at homes along with their poor health conditions have motivated the development of a home monitoring system which aims at improving their wellness and health-care. The purpose of this system is to monitor the physiological parameters in real time, together with the help from a computer vision module. Several research works on this area have been conducted, however, the combination of image processing and wearable sensors have not been widely reported. The daily activities and health parameters are to be further analyzed. In case of any abnormal or emergency situations, alarm will be triggered and urgent message will be sent to a medical doctor.
This thesis looks at the problem of channel estimation and equalization in a multiple-input multi... more This thesis looks at the problem of channel estimation and equalization in a multiple-input multiple-output (MIMO) dispersive fading environments. Two classes of MIMO receiver structure are proposed with integrated channel estimation and tracking. One is a symbol-by-symbol based receiver using a MIMO minimum mean square error (MMSE) decision feedback equalizer (DFE), and the other is a sequence-based receiver using a partitioned Viterbi algorithm (PVA) which approaches the performance of maximum likelihood sequence estimation (MLSE). A MIMO channel estimator capable of tracking the time and frequency selective channel impulse responses, known as the vector generalized recursive least squares (VGRLS) algorithm, is developed. It has comparable performance and a similar level of complexity as the optimum Kalman filter. However, it does not require any knowledge of the channel statistics to operate and as such it can be employed in a Rician fading channel readily. A reduced complexity f...
In this paper, non-orthogonal multiple access (NOMA) with successive interference cancellation (S... more In this paper, non-orthogonal multiple access (NOMA) with successive interference cancellation (SIC) technique for downlink channel of next generation wireless network and its security issues are discussed. In NOMA, signals for all user equipment (UEs) are superimposed before transmission and then decoded at each UE implementing SIC. SIC relies on decoding and subtracting the signals in sequence until it reaches its desired signal. The decoding order at each UE, however, must match with the user index in the cancellation sequence. In case of mismatch, UEs will not obtain their signals and re-request their messages from the BS which will further increase the processing time that is already high for a regular SIC receiver. Numerical results show the performance of SIC at the UE side. The time spent for decoding the received signal at the UE with and without user mismatch is discussed. The unusual longer decoding times are further discussed as potential external network threat.
Capstone project (CP) is an integral part of an undergraduate engineering degree. It is important... more Capstone project (CP) is an integral part of an undergraduate engineering degree. It is important because it gives students the opportunity to demonstrate the breadth of knowledge and skills that they have learnt in the whole of their undergraduate courses. It is therefore critical to have a well-defined and well-designed CP as a concluding part to a Bachelor degree engineering program especially in demonstrating that students and the program fulfil the accreditation requirements of relevant accreditation bodies. In this paper, we discuss how these CP assessment tasks can be conducted such that they can be mapped to most of the 42 points within the 6 broad categories of the Engineering Council UK (ECUK) graduate competencies requirements.
With the abundance of ubiquitous transmission of wireless signals nowadays due to the proliferati... more With the abundance of ubiquitous transmission of wireless signals nowadays due to the proliferation of wireless devices, these man-made radio frequency signals in the form of electromagnetic waves can be exploited in various forms, for example localization and tracking. Here, we describe how these signals can be used in sensing an object or human in the environment. We describe the design concept and implementation of an indoor passive tracking system that utilises an array of Wi-Fi transceivers, and without any electronic device or tag attached to the object being tracked. The sensing of an object or a person described here is made possible by exploiting the fundamental characteristic of signal attenuation due to blocking, i.e. shadowing, that is prevalent in a typical wireless communication system. By detecting significant signal attenuation in the system (i.e. by measuring the received signal strength value), it is possible to infer that an object is blocking the line-of-sight (L...
2018 International Conference on Computing and Network Communications (CoCoNet)
Non-orthogonal multiple access (NOMA) is a promising method for the fifth generation (5G) cellula... more Non-orthogonal multiple access (NOMA) is a promising method for the fifth generation (5G) cellular networks as it provides improved spectral efficiency by multiplexing users in power domain. One key challenge for the receivers in NOMA networks is to distinguish the individual signals that use the same band at the same time. Currently, the two widely discussed decoding schemes are successive interference cancellation (SIC) and parallel interference cancellation (PIC). Both schemes suppress the multi-user interference by subtracting the decoded signals from the received signal based on different algorithms, i.e., SIC decodes iteratively and PIC decodes collectively. This paper compares the computation time of SIC and PIC schemes at the base station and demonstrates multi-thread implementation of PIC.
This paper presents a Generalized Power Allocation (GPA) scheme for different users in Non-Orthog... more This paper presents a Generalized Power Allocation (GPA) scheme for different users in Non-Orthogonal Multiple Access (NOMA) based wireless communication system. The power allocation to the users becomes complex with the increased number of users. There are some conventional schemes for power allocation in NOMA but they have to optimize some parameters arbitrarily. In this paper, a simple but effective power allocation scheme has been formulated and tested by simulations. The proposed GPA scheme does not need any parameter adjustment. Theoretical power distribution to different users of NOMA has been calculated using the proposed GPA technique. The calculated powers of individual users with the proposed scheme are different and more distributed than the arbitrary power allocation scheme which satisfies the basic condition of NOMA. The total of calculated powers with GPA scheme shows only 01% variation with the arbitrary power allocation scheme which shows the consistency of GPA scheme with other schemes. The performance of NOMA based wireless communication system with GPA scheme has been simulated under various conditions using Matlab. The simulated BER performance for NOMA based wireless communication system using different modulation techniques show similar results with other conventional schemes which validates the formulation of GPA scheme.
This thesis looks at the problem of channel estimation and equalization in a multiple-input multi... more This thesis looks at the problem of channel estimation and equalization in a multiple-input multiple-output (MIMO) dispersive fading environments. Two classes of MIMO receiver structure are proposed with integrated channel estimation and tracking. One is a symbol-by-symbol based receiver using a MIMO minimum mean square error (MMSE) decision feedback equalizer (DFE), and the other is a sequence-based receiver using a partitioned Viterbi algorithm (PVA) which approaches the performance of maximum likelihood sequence estimation (MLSE). A MIMO channel estimator capable of tracking the time and frequency selective channel impulse responses, known as the vector generalized recursive least squares (VGRLS) algorithm, is developed. It has comparable performance and a similar level of complexity as the optimum Kalman filter. However, it does not require any knowledge of the channel statistics to operate and as such it can be employed in a Rician fading channel readily. A reduced complexity f...
TENCON 2009 - 2009 IEEE Region 10 Conference, 2009
ABSTRACT The error rate performance of a previously developed reduced complexity channel estimato... more ABSTRACT The error rate performance of a previously developed reduced complexity channel estimator, known as the generalized least mean squares (GLMS) algorithm, is investigated in conjunction with a minimum-mean-square-error (MMSE) decision feedback equalizer (DFE). The channel estimator is based on the theory of polynomial prediction and Taylor series expansion of the underlying channel model in time domain. It is a simplification of a previously developed generalized recursive least squares (GRLS) estimator, achieved by replacing the online recursive computation of the `intermediate' matrix by an offline pre-computed matrix. Similar to the GRLS estimator, it is able to operate in Rayleigh or Rician fading environment without reconfiguration of the state transition matrix to accommodate the non-random mean components. Simulation results show that it is able to offer a trade-off between reduced complexity channel estimation and good system performance.
IET 2nd International Conference on Wireless, Mobile and Multimedia Networks (ICWMMN 2008), 2008
ABSTRACT The error rate performance of a previously developed reduced complexity channel estimato... more ABSTRACT The error rate performance of a previously developed reduced complexity channel estimator, known as the generalized least mean squares (GLMS) algorithm, is investigated in conjunction with a minimum-mean-square-error (MMSE) decision feedback equalizer (DFE). The channel estimator is based on the theory of polynomial prediction and Taylor series expansion of the underlying channel model in time domain. It is a simplification of the generalized recursive least squares (GRLS) estimator, achieved by replacing the online recursive computation of the ‘intermediate’ matrix by an offline pre-computed matrix. Similar to the GRLS estimator, it is able to operate in Rayleigh or Rician fading environment without reconfiguration of the state transition matrix to accommodate the non-random mean components. Simulation results show that it is able to offer a trade-off between reduced complexity channel estimation and good system performance.
2015 9th International Conference on Sensing Technology (ICST), 2015
Ieee Transactions on Vehicular Technology, Feb 1, 2009
A sequence-based multiple-input-multiple-output receiver incorporating channel estimation and tra... more A sequence-based multiple-input-multiple-output receiver incorporating channel estimation and tracking for a frequency selective fading environment is developed. It employs near-maximum likelihood sequence estimation using the partitioned Viterbi algorithm and offers linearly increasing complexity with the number of transmit antennas. The receiver implements channel estimation and tracking using a vector-polynomial-based generalized recursive least squares algorithm. The resulting integrated receiver can operate in a continuously time-varying Rayleigh or Rician fading environment. Simulation results show that it offers a good tradeoff between complexity and performance. Further complexity reduction can be achieved using tentative decisions as reference signals to the estimator and a reduced complexity form of the estimator.
2015 9th International Conference on Sensing Technology (ICST), 2015
2015 International Conference on Computer, Communications, and Control Technology (I4CT), 2015