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Introduction
Pei Xiao currently works at the Institute for Communication Systems (ICS), University of Surrey. Pei does research in Electronic Engineering, Telecommunications Engineering and Communication Engineering. Their most recent publication is 'Low-Complexity and Robust Hybrid Beamforming Design for Multi-Antenna Communication Systems'.
Current institution
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January 2011 - May 2016
Publications
Publications (626)
Semantic communications have emerged as a crucial research direction for future wireless communication networks. However, as wireless systems become increasingly complex, the demands for computation and communication resources in semantic communications continue to grow rapidly. This paper investigates the trade-off between computation and communic...
In this letter, a novel class of sparse codebooks is proposed for sparse code multiple access (SCMA) aided non-terrestrial networks (NTN) with randomly distributed users characterized by Rician fading channels. Specifically, we first exploit the upper bound of bit error probability (BEP) of an SCMA-aided NTN with large-scale fading of different use...
A novel polarization reconfigurable anisotropic dielectric resonator antenna (ADRA) is presented utilizing a new modulation scheme to exploit the degree of freedom in the polarization domain. The ADRA comprises periodic assembly dielectric resonators with two different dielectrics constant, equal in size, a vertically positioned metal strip, one va...
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In this paper, we propose a novel active reconfigurable intelligent surface (RIS)-assisted amplitude-domain reflection modulation (ADRM) transmission scheme, termed as ARIS-ADRM. This innovative approach leverages the additional degree of freedom (DoF) provided by the amplitude domain of the active RIS to perform index modulation (IM), thereby enha...
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Affine frequency division multiplexing (AFDM) is a promising chirp-assisted multicarrier waveform for future high-mobility communications. This paper is devoted to enhanced receiver design for multiple input and multiple output AFDM (MIMO-AFDM) systems. Firstly, we introduce a unified variational inference (VI) approach to approximate the target po...
Sparse code multiple access (SCMA) and multiple input multiple output (MIMO) are considered as two efficient techniques to provide both massive connectivity and high spectrum efficiency for future machine-type wireless networks. This paper proposes a single sparse graph (SSG) enhanced expectation propagation algorithm (EPA) receiver, referred to as...
This paper investigates joint location and velocity estimation, along with their fundamental performance bounds analysis, in a cell-free multi-input multi-output (MIMO) integrated sensing and communication (ISAC) system. First, unlike existing studies that derive likelihood functions for target parameter estimation using continuous received signals...
Edge computing improves the Internet of Vehicles (IoV) by offloading heavy computations from in-vehicle devices to high-capacity edge servers, typically roadside units (RSUs), to ensure rapid response times for intensive and latency-sensitive tasks. However, maintaining quality of service (QoS) remains challenging in dense urban settings and remote...
This paper introduces a novel iterative algorithm for optimizing pilot and data power control (PC) in cell-free massive multiple-input multiple-output (CF-mMIMO) systems, aiming to enhance system performance under real-time channel conditions. The approach begins by deriving the signal-to-interference-plus-noise ratio (SINR) using a matched filteri...
In this paper, we investigate a cell-free massive multiple-input and multiple-output (MIMO)-enabled integration communication, computation, and sensing (ICCS) system, aiming to minimize the maximum computation latency to guarantee the stringent sensing requirements. We consider a two-tier offloading framework, where each multi-antenna terminal can...
Next-generation wireless networks are conceived to provide reliable and high-data-rate communication services for diverse scenarios, such as vehicle-to-vehicle, unmanned aerial vehicles, and satellite networks. The severe Doppler spreads in the underlying time-varying channels induce destructive inter-carrier interference (ICI) in the extensively a...
Sparse code multiple access (SCMA) is a promising technique for future machine type communication systems due to its superior spectral efficiency and capability for supporting massive connectivity. This paper proposes a novel class of sparse codebooks to improve the error rate performance of SCMA in the presence of phase noise (PN). Specifically, w...
Integrated sensing and communication (ISAC) is a promising solution to mitigate the increasing congestion of the wireless spectrum. In this paper, we investigate the short packet communication regime within an ISAC system assisted by a reconfigurable intelligent surface (RIS) to meet the low latency ultra-reliable requirements in the next-generatio...
The combination of multiple-input multiple-output (MIMO) and sparse code multiple access (SCMA), referred to as MIMO-SCMA, can be leveraged to achieve high spectrum efficiency and provide massive connectivity for future machine -type communication networks. This paper aims to design enhanced sparse codebooks for MIMO-SCMA by jointly combining frequ...
The downlink channel reconstruction at the base station holds paramount significance across a multitude of applications in FDD massive MIMO systems. Conventional approaches rely on downlink training and feedback with a considerable overhead. In order to mitigate this issue, we propose a tensor-based framework for downlink channel reconstruction tha...
Sparse code multiple access (SCMA) is a promising non-orthogonal multiple access scheme for enabling massive connectivity in next generation wireless networks. However, current SCMA codebooks are designed with the same size, leading to inflexibility of user grouping and supporting diverse data rates. To address this issue, we propose a variable mod...
Low-Earth orbit (LEO) satellites are envisioned as a fundamental component in future 6G communications by virtue of their capability to provide global coverage with low-cost deployment. Most existing LEO satellite communication systems rely on terrestrial core networks to complete end-to-end data transmission. As LEO satellites are expected to be e...
Time-frequency localization (TFL) based intelligent wideband spectrum sensing is capable of achieving precise dynamic spectrum management. Recent studies demonstrate that object detectors can achieve excellent TFL performance in simple electromagnetic scenarios when trained with massive and labeled datasets. However, in real-world concurrent cognit...
Existing studies show that the non-coherent joint transmission (NCJT) serving mode can outperform the coherent joint transmission (CJT) serving mode in terms of energy efficiency (EE) in cell-free massive multi-input multi-output (CF-mMIMO) systems with limited fronthauls, although the CJT can achieve prominent coherent cooperative gain. However, r...
Traditional grid-based compressed sensing algorithms usually suffer from the base mismatch effect in channel estimation problems. To address this, we propose a novel gridless uplink/downlink (UL/DL) channel estimation strategy for millimeter wave (mmWave) massive multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM)...
Sparse code multiple access (SCMA) is a promising technique for future machine type communication systems due to its superior spectral efficiency and capability for supporting massive connectivity. This paper proposes a novel class of sparse codebooks to improve the error rate performance of SCMA in the presence of phase noise (PN). Specifically, w...
In this paper, we propose a novel composition aided generalized quadrature spatial modulation (C-GQSM) scheme to improve the spectral efficiency (SE) of the GQSM systems by exploiting the power domain degree of freedom. The C-GQSM scheme constitutes a hybridization of GQSM and composition modulation (CM) principles, allowing the information bits to...
The importance of Model Parallelism in Distributed Deep Learning continues to grow due to the increase in the Deep Neural Network (DNN) scale and the demand for higher training speed. Different from all the existing works, we propose a model-parallel strategy called NetPlacer+ based on load balance. The major idea in NetPlacer+ is to partition the...
Terahertz (THz) systems can accommodate extremely high data rates thanks to large bandwidth. However, the sensitivity to blockages is a key challenge for THz signals, and even user position variation may cause misalignment of THz pencil-like beamforming resulting in sharp decline in system performance. In this paper, we propose a novel system perfo...
This paper introduces a method for target tracking that leverages mobile sensor nodes and Unmanned Aerial Vehicles (UAVs) within an Open- Radio Access Network (RAN) framework. Open-RAN is a flexible and standardized architecture that allows open and interoperable components in RANs, promoting efficiency and adaptability. The core methodology involv...
Advances in wireless technology have significantly increased the number of wireless connections, leading to higher energy consumption in networks. Among these, base stations (BSs) in radio access networks (RANs) account for over half of the total energy usage. To address this, we propose a multi-cell sleep strategy combined with adaptive cell zoomi...
Advances in wireless technology have significantly increased the number of wireless connections, leading to higher energy consumption in networks. Among these, base stations (BSs) in radio access networks (RANs) account for over half of the total energy usage. To address this, we propose a multi-cell sleep strategy combined with adaptive cell zoomi...
In this paper, we introduce a novel framework consisting of hybrid bit-level and generative semantic communications for efficient downlink image transmission within space-air-ground integrated networks (SAGINs). The proposed model comprises multiple low Earth orbit (LEO) satellites, unmanned aerial vehicles (UAVs), and ground users. Considering the...
Rate Splitting Multiple Access (RSMA) precoder design with the practical finite-alphabet constellations instead of Gaussian inputs has been addressed in this paper. Considering a multiuser (MU) multiple-input single-output (MISO) broadcast channel (BC) system, we derive a generalized expression of the achievable rate for each user, in a way that th...
In this paper, we investigate a novel integrated communications, computing, and sensing (ICCS) network, where amulti-functional base station (BS) performs down link communication, target sensing and edge computing.Toexaminetheoverall performance of the system under consideration, a weighted sum rate (WSR) maximization problem is formulated by joint...
The design of efficient sparse codebooks in sparse code multiple access (SCMA) system have attracted tremendous research attention in the past few years. This paper proposes a novel nonlinear SCMA (NL-SCMA) that can subsume the conventional SCMA system which is referred to as linear SCMA, as special cases for downlink channels. This innovative appr...
Sparse code multiple access (SCMA) is a promising non-orthogonal multiple access scheme for enabling massive connectivity in next generation wireless networks. However, current SCMA codebooks are designed with the same size, leading to inflexibility of user grouping and supporting diverse data rates. To address this issue, we propose a variable mod...
A specific limitation of spatial modulation (SM) is that the number of transmit antennas must be a power of two, otherwise it will cause a fractional bits problem. To solve this problem, this paper proposes a novel transmission scheme, called golden angle modulation aided fractional spatial modulation (GAM-FSM), which exploits the property of golde...
This paper studies the affine frequency division multiplexing (AFDM)-empowered sparse code multiple access (SCMA) system, referred to as AFDM-SCMA, for supporting massive connectivity in high-mobility environments. First, by placing the sparse codewords on the AFDM chirp subcarriers, the input-output (I/O) relation of AFDM-SCMA systems is presented...
Generative foundation AI models have recently shown great success in synthesizing natural signals with high perceptual quality using only textual prompts and conditioning signals to guide the generation process. This enables semantic communications at extremely low data rates in future wireless networks. In this paper, we develop a latency-aware se...
This paper proposes an intelligent reflecting surface (IRS) assisted integrated sensing and communication (ISAC) system operating in the millimeter-wave band. Specifically, the ISAC system consists of a radar subsystem and a communication subsystem to detect multiple targets and communicate with the users simultaneously. The IRS is used to configur...
This paper develops an edge-device collaborative Generative Semantic Communications (Gen SemCom) framework leveraging pre-trained Multi-modal/Vision Language Models (M/VLMs) for ultra-low-rate semantic communication via textual prompts. The proposed framework optimizes the use of M/VLMs on the wireless edge/device to generate high-fidelity textual...
Most of the existing research on degrees-of-freedom (DoF) with imperfect channel state information at the transmitter (CSIT) assume the messages are private, which may not reflect reality as the two receivers can request the same content. To overcome this limitation, we therefore consider the hybrid unicast and multicast messages. In particular, we...
Compressed sensing (CS)-based techniques have been widely applied in the grant-free non-orthogonal multiple access (NOMA) to a single-antenna base station (BS). In this paper, we consider the multi-antenna reception at the BS for uplink grant-free access for the massive machine type communication (mMTC) with limited channel resources. To enhance th...
Sparse code multiple access (SCMA) is a promising technique for enabling massive connectivity and high spectrum efficiency in future machine-type communication networks. However, its performance crucially depends on well-designed multi-dimensional codebooks. In this paper, we propose a novel progressive codebook optimization scheme that can achieve...
Satellite communications have attracted significant interests due to its advantages of large footprint and massive access. However, the commonly used onboard beamforming is hard to achieve reliable security because of the highly correlated legitimate and wiretap downlink channels. We exploit the benefits of satellite-terrestrial integrated network...
With line-of-sight mode deployment and fast response, unmanned aerial vehicle (UAV), equipped with the cutting-edge integrated sensing and communication (ISAC) technique, is poised to deliver high-quality communication and sensing services in maritime emergency scenarios. In practice, however, the real-time transmission of ISAC signals at the UAV s...
The space-air-ground integrated network (SAGIN) has become a crucial research direction in future wireless communications due to its ubiquitous coverage, rapid and flexible deployment, and multi-layer cooperation capabilities. However, integrating hierarchical federated learning (HFL) with edge computing and SAGINs remains a complex open issue to b...
The space-air-ground integrated network (SAGIN) has become a crucial research direction in future wireless communications due to its ubiquitous coverage, rapid and flexible deployment, and multi-layer cooperation capabilities. However, integrating hierarchical federated learning (HFL) with edge computing and SAGINs remains a complex open issue to b...
Satellite communications are perceived as an essential supplement to terrestrial networks due to their benefits of providing seamless coverage and global connectivity. On the basis of existing multiple-input multiple-output (MIMO) satellite communication, the large-scale MIMO technology, which is capable of fully exploring spatial degrees of freedo...
In this paper, we propose a transmission mechanism for fluid antennas (FAs) enabled multiple-input multiple-output (MIMO) communication systems based on index modulation (IM), named FA-IM, which incorporates the principle of IM into FAs-assisted MIMO system to improve the spectral efficiency (SE) without increasing the hardware complexity. In FA-IM...
Reconfigurable intelligent surfaces (RISs) have emerged as a promising technology in wireless communications. Simultaneously transmitting and reflecting RIS (STAR-RISs) in particular have garnered significant attention due to their dual capabilities of simultaneous transmission and reflection, underscoring their potential applications in critical s...
Reconfigurable intelligent surfaces (RISs) have emerged as a promising technology in wireless communications. Simultaneously transmitting and reflecting RIS (STAR-RISs) in particular have garnered significant attention due to their dual capabilities of simultaneous transmission and reflection, underscoring their potential applications in critical s...
In this paper, a golden angle modulation (GAM) aided differential orthogonal frequency division multiplexing with index modulation (DOFDM-IM-GAM) system for low-earth orbit (LEO) satellite communications is proposed, which amalgamates the concept of differential coding to exploit the advantage of GAM and OFDM-IM without channel state information (C...
Phase-shifter-aided spatial multiplexing (PSSM) is a low-complexity multiple-input multiple-output (MIMO) technique with the assistance of extra phase shifters. Following the basic structure of the PSSM transmitter, in this contribution, a message passing detector tailored for PSSM systems is developed, and is further simplified according to the pa...
Generative foundation AI models have recently shown great success in synthesizing natural signals with high perceptual quality using only textual prompts and conditioning signals to guide the generation process. This enables semantic communications at extremely low data rates in future wireless networks. In this paper, we develop a latency-aware se...
Compressed sensing (CS)-based techniques have been widely applied in the grant-free non-orthogonal multiple access (NOMA) to a single-antenna base station (BS). In this paper, we consider the multi-antenna reception at the BS for uplink grant-free access for the massive machine type communication (mMTC) with limited channel resources. To enhance th...
Motivated by the need for increased spectral efficiency and the proliferation of intelligent applications, the sixth-generation (6G) mobile network is anticipated to integrate the dual-functions of communication and sensing (C&S). Although the millimeter wave (mmWave) communication and mmWave radar share similar multiple-input multiple-output (MIMO...
Physical layer security (PLS) technologies are expected to play an important role in the next-generation wireless networks, by providing secure communication to protect critical and sensitive information from illegitimate devices. In this paper, we propose a novel secure communication scheme where the legitimate receiver use full-duplex (FD) techno...
This paper studies the codebook design for sparse code multiple access (SCMA) based visible light communication (VLC) impaired by shot noise. By focusing on the typical Rician fading channels, we first derive a lower bound of the mutual information of VLC with shot noise and present a design metric called minimum normalized Euclidean distance (MNED...
In this paper, a wireless channel sounding campaign was conducted in a land-to-ship scenario at 3.2GHz. The ship, equipped with a transmitter (TX), passed islands during measurement while the stationary receiver (RX) remained on land. Based on the measured data, the wireless channel characteristics in scenarios featuring islands were analyzed and a...
In the Industrial Internet of Things (IIoT), outdoor electronic devices serve crucial roles across sectors, providing vital data for decision-making. However, their exposure to open outdoor environments makes them vulnerable to unauthorized access, physical theft, or compromise, endangering both the device and its data. Ensuring the security of out...
The Internet of Things (IoT) introduces diverse requirements and ubiquitous connections, necessitating efficient and affordable energy consumption as the ecosystem continues to grow. To address this challenge, we investigate a pure non-orthogonal multiple access (pure-NOMA) beamforming scheme to enhance system capacity by accommodating more IoT dev...
In this paper, we propose a fluid antenna (FA) enabled joint transmit and receive index modulation (FA-JTR-IM) transmission mechanism for reconfigurable intelligent surface (RIS)-assisted millimeter-wave (mmWave) communication systems. By integrating the methodologies of FA and IM, the proposed scheme achieves enhanced spectral efficiency (SE) whil...
In recent years, the amalgamation of satellite communications and aerial platforms into space-air-ground integrated network (SAGINs) has emerged as an indispensable area of research for future communications due to the global coverage capacity of low Earth orbit (LEO) satellites and the flexible Deployment of aerial platforms. This paper presents a...
In this paper, the harmony between non-orthogonal multiple access (NOMA) and rate-splitting (RS) is explored in a multi-antenna scenario, where a RS-NOMA system is proposed to implement dynamically transformation between these two transmission schemes. Specifically, a common signal is generated at the base station (BS) and transmitted with the user...
In this paper, we propose golden angle modulation aided orthogonal frequency division multiplexing with index modulation (OFDM-IM-GAM) for an arbitrary number of subcarriers, which includes integer OFDM-IM-GAM (I-OFDM-IM-GAM) and fractional OFDM-IM-GAM (F-OFDM-IM-GAM). Furthermore, a general mapping optimization algorithm is developed for our propo...
5G Non-Terrestrial Network (NTN) technology has successfully triggered the convergence across satellite and mobile cellular ecosystems. Compared with proprietary technologies, the open standard 5G NTN technology can enable satellite communications in more affordable devices and mainstream consumer markets thanks to economics of scale. The recent ex...
With exploiting massive spectrum resources, millimeter wave (mmWave) communications significantly improve the offloading capability for future mobile edge computing (MEC) techniques, which however is constrained by blockage problem in dynamic environments. In this paper, we study the resource allocation problem for the conceived mmWave MEC system w...
This letter studies high-capacity visible light communication (VLC) based on code-domain non-orthogonal multiple access (CD-NOMA) with the goal of enabling the future machine-type communication networks. To fulfill the non-negative signal constraint and mitigate/suppress the nonlinear effects and shot noise, a novel uniform-distributed constellatio...
Citation: Hamdan, M.Q.; Lee, H.; Triantafyllopoulou, D.; Borralho, R.; Kose, A.; Amiri, E.; Mulvey, D.; Yu, W.; Zitouni, R.; Pozza, R.; et al. Recent Advances in Machine Learning for Network Automation in O-RAN. Sensors 2023, 23, 8792. Abstract: The evolution of network technologies has witnessed a paradigm shift toward open and intelligent network...
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This work presents a novel K-Repetition based Hybrid Automatic Repeat reQuest (HARQ) scheme for uplink sparse code multiple access (SCMA) systems. Our core idea is to apply network coding (NC) principle to re-encode different packets (after channel coding and interleaving) or their fragments, where K-Repetition is an emerging HARQ technique (recomm...
This paper proposes learning-based joint optimization of unmanned aerial vehicle (UAV) trajectory and reconfigurable intelligent surface (RIS) reflection coefficients in UAV-RIS-assisted cognitive non-terrestrial networks (NTNs) to enhance the secrecy performance. The practical RIS phase shift model, outdated channel state information (CSI) and int...
This paper conceives a novel sparse code multiple access (SCMA) codebook design which is motivated by the strong need for providing ultra-low decoding complexity and good error performance in downlink Internet-of-things (IoT) networks, in which a massive number of low-end and low-cost IoT communication devices are served. By focusing on the typical...
Edge computing is a viable paradigm for supporting the Industrial Internet of Things deployment by shifting computationally demanding tasks from resource-constrained devices to powerful edge servers. In this study, mobile edge computing (MEC) services are provided for multiple ground mobile nodes (MNs) through a time-division multiple access protoc...
This paper analyzes the maximal achievable rate for a given blocklength and maximal error probability over a multiple-antenna ambient backscatter channel. The result consists of a finite blocklength channel coding achievability bound and a converse bound for the legacy system with finite alphabet constraints and multiple-input-multiple-output based...
Physical layer security (PLS) technologies are expected to play an important role in the next-generation wireless networks, by providing secure communication to protect critical and sensitive information from illegitimate devices. In this paper, we propose a novel secure communication scheme where the legitimate receiver use full-duplex (FD) techno...
Wireless powered mobile edge computing (WP-MEC) has been recognized as a promising solution to enhance the computational capability and sustainable energy supply for low-power wireless devices (WDs). However, when the communication links between the hybrid access point (HAP) and WDs are hostile, the energy transfer efficiency and task offloading ra...
Sparse code multiple access (SCMA) is a promising technique for the enabling of massive connectivity in future machine-type communication networks, but it suffers from a limited diversity order which is a bottleneck for significant improvement of error performance. This paper aims for enhancing the signal space diversity of sparse code multiple acc...
