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Dr Adegbenga Awoseyila


Senior Research Fellow
+44 (0)1483 689124
42 BA 01

Academic and research departments

5G Innovation Centre.

Supervision

Postgraduate research supervision

Courses I teach on

Postgraduate taught

CPD and Short courses

My publications

Publications

Awoseyila AB, Kasparis C, Evans BG (2009) Robust Time-domain Timing and Frequency Synchronization for OFDM Systems, IEEE T CONSUM ELECTR 55 (2) pp. 391-399 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
A robust and efficient technique for frame/symbol timing and carrier frequency synchronization in OFDM systems is presented. It uses a preamble consisting of only one training symbol with two identical parts to achieve reliable timing and frequency accuracy in the time-domain, over a wide-frequency estimation range which can be up to half of the signal sampling frequency. Also, it has a loti, complexity which is adaptive to the degree of channel distortion. Computer simulations in the Rayleigh fading ISI channel show that the proposed method achieves superior performance to existing techniques in terms of timing and frequency accuracy. Also, its operation in the time-domain helps to achieve faster synchronization convergence(1).
Awoseyila AB, Kasparis C, Evans BG (2008) Improved Preamble-Aided Timing Estimation for OFDM Systems, IEEE COMMUNICATIONS LETTERS 12 (11) pp. 825-827 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Afelumo O, Awoseyila AB, Evans BG (2012) Simplified evaluation of APSK error performance, Electronics Letters 48 (14) pp. 886-888 IET
An analytical evaluation of the performance of amplitude phase shift keying constellations in additive white Gaussian noise is performed and an expression to approximate the error probability is presented. The expression accounts for a number of symbols, equal to the number of concentric rings in the constellation. It is shown to significantly reduce the computational complexity associated with previously known error performance expressions, while closely predicting the error rates in the relevant signal-to-noise ratio range.
Ijaz A, Awoseyila AB, Evans BG (2011) Low-complexity time-domain SNR estimation for OFDM systems, Electronics Letters 47 (20) pp. 1154-1156
A low-complexity signal-to-noise ratio (SNR) estimation algorithm for orthogonal frequency division multiplexing (OFDM) systems in frequency-selective fading channels is proposed. The estimator is based on a conventional preamble having two identical parts. It uses the correlation of the received signal samples to estimate signal power while noise power is estimated using the difference between received samples. Simulation results show that the proposed estimator is robust to the channel's frequency selectivity and its attained accuracy and reduced complexity make it an attractive choice for current wireless OFDM systems.
Ijaz A, Awoseyila AB, Evans BG (2012) Signal-to-noise ratio estimation algorithm for advanced DVB-RCS systems, IEEE Transactions on Broadcasting 58 (4) pp. 603-608 IEEE
This paper presents a signal-to-noise ratio (SNR) estimation algorithm for advanced Digital Video Broadcasting - Return Channel via Satellite (DVB-RCS) systems using adaptive coding and modulation (ACM) in the reverse link of broadband satellite systems. Due to the absence of a repetitive pilot symbol structure, SNR estimation has to be performed using the fixed symbol preamble data. Moreover, sporadic nature of data traffic on the return link causes variation in interference level from slot to slot and, therefore, the estimation has to be done within one traffic slot duration. Hence, it becomes necessary to use a combination of data-aided (DA) and decision-directed (DD) algorithms so as to make use of traffic data. A non-data-aided (NDA) estimator that was previously proposed by the authors for binary phase shift keying (BPSK) and QPSK schemes is extended to 8-PSK in a decision directed manner. This estimator shows improved performance over existing estimators. The inherent bias of DD approach at low values of SNR is reduced by using a hybrid approach, i.e. using the proposed estimator at moderate/high values of SNR and the moments-based estimator (M2M4) at low values of SNR. Overall improved performance of the proposed hybrid estimator, in terms of accuracy and complexity, makes it an attractive choice for implementing ACM in advanced DVB-RCS systems.
Ijaz A, Awoseyila AB, Evans BG (2010) Improved SNR estimation for BPSK and QPSK signals, ELECTRONICS LETTERS 45 (16) pp. 858-859 INST ENGINEERING TECHNOLOGY-IET
Awoseyila AB, Evans BG (2010) Improved time diversity for LTE over satellite using split multicode transmission, ELECTRONICS LETTERS 46 (10) pp. 729-U94 INST ENGINEERING TECHNOLOGY-IET
Ijaz A, Awoseyila AB, Evans BG (2011) Enhanced Channel Estimation for DVB-S2 Systems,
Zhu M, Awoseyila AB, Evans BG (2011) Low Complexity Time-Domain Channel Estimation for OFDM Systems, Electronics Letters 47 (1) pp. 60-62 IET
A low-complexity time-domain channel estimation scheme for orthogonal frequency division multiplexing (OFDM) is proposed in the presence of timing synchronisation error. It uses training symbols (preamble) to estimate the channel impulse response where the degradation caused by synchronisation error can be compensated for by an optimisation mechanism. The proposed scheme can be easily integrated with the existing near-ideal synchronisation technique. Simulation results in quasistatic channels show that the proposed method achieves near-ideal accuracy with a complexity much lower than that of the MMSE.
Awoseyila AB, Evans BG, Kasparis C (2011) Frame timing and carrier frequency recovery for frequency selective signals, 09711657.8
The present invention relates to digital receivers in a frequency-selective (wideband) channel and in particular
to frame/symbol timing and carrier frequency synchronization in the reception of orthogonal frequency-division multiplexing
(OFDM) signals. The present invention provides a method of synchronizing a receiver to a received signal, wherein the signal
includes a training symbol having two identical parts, the method including determining a degree of autocorrelation
between parts of the signal at the spacing of the two identical parts, and a degree of cross-correlation between parts of
the received signal and a reference copy of the training symbol, and multiplying together the autocorrelation and crosscorrelation
to determine at least one of the timing and the frequency of the received signal. This may be achieved by multiplying the cross-correlation and autocorrelation directly, or by multiplying a function, which may be referred to as a timing metric, of one of them with the other, or my multiplying functions of both of them together.
Awoseyila AB, Evans BG, Zhu M (2010) Low complexity time-domain channel and delay spread estimation for OFDM systems, IEEE Transactions on Consumer Electronics 56 (4) pp. 2170-2177
A low complexity time-domain channel estimation scheme for OFDM systems is presented. It uses a training symbol (preamble) to estimate the channel impulse response (CIR) in the presence of timing synchronization errors. Its computational complexity is much lower than that of the popular MMSE technique and this can be further reduced if there is prior knowledge of the channel delay spread. Consequently, channel delay spread estimation is also addressed by using threshold setting on the optimized CIR. Computer simulations show that the proposed scheme achieves near-ideal accuracy in quasi-static channels.
Ijaz A, Awoseyila AB, Evans BG (2012) Signal-to-noise ratio estimation algorithm for adaptive coding and modulation in advanced DVB-RCS systems, IET Communications 6 (11) pp. 1587-1593 IET
This paper presents a signal-to-noise ratio (SNR) estimation algorithm for advanced digital video broadcastingreturn channel via satellite (DVB-RCS) systems using adaptive coding and modulation (ACM). Due to the absence of a repetitive pilot symbol structure, SNR estimation has to be performed using the fixed symbol preamble data. Moreover, sporadic nature of data traffic on the return link causes variation in interference level from slot to slot and, therefore, the estimation has to be done within one traffic slot duration. Hence, it becomes necessary to use a combination of data-aided and decision-directed (DD) algorithms so as to make use of traffic data. A non-data-aided estimator that was previously proposed by the authors for binary and quadrature phase shift keying schemes is extended to 8-PSK in a decision directed manner. The inherent bias of DD approach at low values of SNR is reduced by using a hybrid approach, that is, using the proposed estimator at moderate/high values of SNR and the moments-based estimator (M2M4) at low values of SNR. Overall improved performance of the proposed hybrid estimator, in terms of accuracy and complexity, makes it an attractive choice for implementing ACM in advanced DVB-RCS systems.
Rosati S, Awoseyila AB, Vanelli-Coralli A, Kasparis C, Corazza GE, Evans BG (2009) Threshold detection analysis for OFDM timing and frequency recovery, GLOBECOM - IEEE Global Telecommunications Conference
Zhu M, Kasparis C, Awoseyila A, Evans BG (2009) Adaptive inter-carrier interference cancellation technique for OFDM systems, IET Conference Publications (552 CP)
Zhu M, Awoseyila A, Evans BG (2010) Low complexity time-domain channel and delay spread estimation for OFDM systems, IEEE Transactions on Consumer Electronics 56 (4) pp. 2170-2177 IEEE
A low complexity time-domain channel estimation scheme for OFDM systems is presented. It uses a training symbol (preamble) to estimate the channel impulse response (CIR) in the presence of timing synchronization errors. Its computational complexity is much lower than that of the popular MMSE technique and this can be further reduced if there is prior knowledge of the channel delay spread. Consequently, channel delay spread estimation is also addressed by using threshold setting on the optimized CIR. Computer simulations show that the proposed scheme achieves near-ideal accuracy in quasi-static channels.
Zhu M, Awoseyila A, Evans BG (2011) Low-complexity time-domain channel estimation for OFDM systems, ELECTRONICS LETTERS 47 (1) pp. 60-61 INST ENGINEERING TECHNOLOGY-IET
Ijaz A, Awoseyila A, Evans BG (2011) Low-complexity time-domain SNR estimation for OFDM systems, ELECTRONICS LETTERS 47 (20) pp. 1154-1155 INST ENGINEERING TECHNOLOGY-IET
Awoseyila AB, Kasparis C, Evans BG (2008) Improved single frequency estimation with wide acquisition range, Electronics Letters 44 (3) pp. 245-247 Institution of Engineering and Technology
An improved method for estimating the frequency of a single complex sinusoid in complex additive white Gaussian noise is proposed. The method uses a modified version of the weighted linear predictor to achieve optimal accuracy at low/moderate SNR while retaining its speed and wide acquisition range. Consequently, it has an advantage over known methods that use the weighted phase averager since they suffer from an increased threshold effect at frequencies approaching the full estimation range.
Mysore R. Bhavani Shankar, Maleki Sina, Zheng Gan, Awoseyila Adegbenga, Evans Barry, Ottersten Bjorn (2016) GEO Satellite Feeder Links and Terrestrial Full-Duplex Small Cells: A Case for Coexistence, Proceedings of 2016 IEEE 83rd Vehicular Technology Conference (VTC Spring 2016) Institute of Electrical and Electronics Engineers (IEEE)
The demand for wider bandwidths has motivated the need for wireless systems to migrate to higher frequency bands. In line with this trend is an envisaged deployment of Ka-band (or mmWave) cellular infrastructure. Further, to improve the spectral efficiency, developing full-duplex radio transceivers is gaining momentum. In view of this move, the paper proposes the possibility of reusing the satellite feeder uplink band in the full-duplex small cells. The motivation for such a reuse is two-fold :(a) there is virtually no interference from the small cells to the incumbent in-orbit satellite receiver, and (b) directive feeder antennas, with possibly additional isolation and processing causing negligible interference to the small cells. The presented interference analysis clearly supports the proposed coexistence.
Dimitrov Svilen, Privitera Niccolo, Suffritti Rosalba, Boccolini Gabriele, Awoseyila Adegbenga B., Evans Barry G. (2015) Spectrally efficient waveforms for the return link in satellite communication systems, Proceedings of the 2015 European Conference on Networks and Communications (EuCNC 2015) pp. 6-10 Institute of Electrical and Electronics Engineers (IEEE)
In this paper, we study the applicability of terrestrial mobile waveforms in the return link of a high throughput satellite (HTS) communication system. These include orthogonal frequency division multiple access (OFDMA), single-carrier frequency division multiple access (SC-FDMA) and filter bank multi-carrier (FBMC). Key solutions to the challenges in a geostationary orbit (GEO) satellite channel, such as synchronization and non-linear distortion, are presented. A global-positioning-system-(GPS)-based approach for synchronization acquisition is proposed, while suitable algorithms are studied for timing/frequency offset estimation and synchronization tracking. The spectral and power efficiencies of the schemes are optimized by means of an intermodulation interference (IMI) cancelling receiver, and these are compared to state-of-the-art time division multiple access (TDMA). Finally, end-to-end simulations validate the system performance.
Guidotti Alessandro, Vanelli-Coralli Alessandro, Conti Matteo, Andrenacci Stefano, Chatzinotas Symeon, Maturo Nicola, Evans Barry, Awoseyila Adegbenga, Ugolini Alessandro, Foggi Tommaso, Gaudio Lorenzo, Alagha Nader, Cioni Stefano (2019) Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites, IEEE Transactions on Vehicular Technology 68 (3) pp. 2624-2639 Institute of Electrical and Electronics Engineers (IEEE)
Satellite communication systems are a promising solution to extend and complement terrestrial networks in unserved or under-served areas, as reflected by recent commercial and standardization endeavors. In particular, 3GPP recently initiated a study item for new radio, i.e., 5G, non-terrestrial networks aimed at deploying satellite systems either as a stand-alone solution or as an integration to terrestrial networks in mobile broadband and machine-type communication scenarios. However, typical satellite channel impairments, as large path losses, delays, and Doppler shifts, pose severe challenges to the realization of a satellite-based NR network. In this paper, based on the architecture options currently being discussed in the standardization fora, we discuss and assess the impact of the satellite channel characteristics on the physical and medium access control layers, both in terms of transmitted waveforms and procedures for enhanced mobile broadband and narrowband-Internet of Things applications. The proposed analysis shows that the main technical challenges are related to the PHY/MAC procedures, in particular random access, timing advance, and hybrid automatic repeat request and depending on the considered service and architecture, different solutions are proposed.
Evans Barry, Kyrgiazos Argyrios, Arapoglou Pantelis-Daniel, Jeannin Nicolas, Awoseyila Adegbenga (2017) Earth Resource Satellite downlink and ACM Loop Performance at EHF Bands, Proceedings of the 23rd Ka and Broadband Communications Conference (Kaconf 2017) Ka and Broadband Communications, Navigation and Earth Observation Conference
Jayaprakash Arunprakash, Chen Hongzhi, Xiao Pei, Evans Barry G., Zhang Yingnan, Li Jing Yuan, Awoseyila Adegbenga (2019) Analysis of Candidate Waveforms for Integrated Satellite-Terrestrial 5G Systems, Proceedings of the 2019 IEEE 2nd 5G World Forum (5GWF?19)
Satellites will play an indispensable part in 5G roll
out and the common use of new radio (NR) air interface will
enable this. Satellite-terrestrial integration requires adaptations
to the existing NR standards and demands further study on the
potential areas of impact. From a physical layer perspective,
the candidate waveform has a critical role in addressing design
constraints to support non-terrestrial networks (NTN). In this paper,
the adaptability of frequency-localized orthogonal frequency
division multiplexing (OFDM)-based candidate waveforms and
solutions are discussed in the context of physical layer attributes
of non-linear satellite channel conditions. The performance of
the new air interface waveforms are analysed in terms of
spectral confinement, peak-to-average power ratio (PAPR), power
amplifier efficiency, robustness against non-linear distortions and
carrier frequency offset (CFO).
Jayaprakash Arunprakash, Evans Barry G., Xiao Pei, Awoseyila Adegbenga, Zhang Yingnan (2020) New Radio Numerology and Waveform Evaluation
for Satellite Integration into 5G Terrestrial Network,
IEEE International Conference on Communications
This paper analyses the New Radio (NR) air interface
waveforms and numerologies in the context of current
activities and studies of 3GPP related to the feasibility and standardisation of necessary adaptations for the 5G NR to support integrated-satellite-terrestrial networks with low earth orbit (LEO) satellites. Frequency-localized orthogonal frequency
division multiplexing (OFDM)-based candidate waveforms are recommended by 3GPP as the waveforms for the NR in order to preserve the advantages of OFDM as well as maintain backward compatibility. 5G New Radio enables diverse service support, efficient synchronization and channel adaptability using a multinumerology
concept, which defines a family of parameters of the
parent waveform, that are related to each other by scaling. The major design challenges in the LEO satellite scenario are power limited link budget and high Doppler effects which can be addressed by choosing waveforms with small peak to average power ratio (PAPR) and sub-carrier bandwidth adaptation respectively.
Hence, the selection of the right waveform and numerology is of prime relevance for the proper adaptation of 5G NR for LEO satellite terrestrial integration. The performance evaluation of the new air interface waveforms, with different numerologies, are
carried out under the effect of carrier frequency offset (CFO), multipath effects, non-linearity, phase noise and additive white Gaussian noise (AWGN).