Within the Telecommunications Laboratory we offer full-time PhD programs, as well as full-time or part-time Masters by Research programs. We are continually on the lookout for bright and motivated people interested in these programs. For information on specific projects please follow the Research Projects link (on the bottom of this page.) There are opportunities for new students on most projects, so let us know what interestes you.
For application forms, please follow the links on the bottom of this page. We strongly encourage you to make contact with individual staff members from the Telecommunications Laboratory, in order to obtain more detailed information on their projects.
For general information relating to postgraduate study within the department, and for information on scholarships, please visit the Departmental Postgraduate page.
Interference Cancellation in Co-working WLANs
Capacity of cellular networks, such as 3G CDMA, B3G HSPA and LTE, are interference-limited. This means that the maximum number of users in each cell and overall system capacity mainly depend on the signal to interference plus noise (SINR) level. Therefore, how to eliminate the interference is one of most crucial issues to be resolved in future wireless networks. The project aims to reduce interference caused by co-working wireless local area networks (WLANs) and WiMax systems. These WLANs can be either non-cooperative or co-operative. The project will focus on improving Physical (PHY) layer and its interaction with MAC layer through the use of cross-layer design, adaptive modulation, coding, adaptive antennas, co-operation between co-working WLANs and interference cancellation.
Supervisor: Branka Vucetic and Yonghui Li
Dynamic Spectrum Access for wireless multi-Hop cognitive radio networks
Unlike the wired Internet, the wireless world has a limited amount of links to distribute. Consequently, the traditional regulation of spectrum requires a fundamental reform in order to allow for more efficient and creative use of the precious resource of the airwaves. Cognitive radio and its particular version of dynamic spectrum access are promising techniques to increase the efficiency of spectrum utilization. They allow un-licensed users to coexist in licensed bands. Dynamic spectrum access senses transmission in a particular licensed frequency band, identifies unused radio spectrum and leaves it when the incumbent radio system is ready to transmit.
In this project we will we will develop dynamic spectrum access techniques for cognitive multi-hop local area networks and establish a general framework for the theory and design of multi-hop cognitive networks. We will address several crucial challenges in designing a multi-hop cognitive network with a potential to achieve significant advances in spectrum utilization and management.
This project aims to apply graph theories, such as random geometric graphs and evolving graphs, to investigate on these network properties and their relations to other network conditions such as network density and energy constraint. The research results will contribute to the design and implementation of wireless multi-Hop cognitive radio networks.
Supervisor: Yonghui Li and Branka Vucetic
Precoded Multiuser MIMO and Packet Scheduling
Linear precoding for multiuser Multiple-Input Multiple-Output (MIMO) systems has attracted much attention recently due to the capacity enhancement ability at the system level. In the existing literature, the interactions between packet scheduling and array antenna techniques are studied based on system level simulation models. To our knowledge, theoretical analysis of linearly precoded multiuser Spatial Division Multiplexing (SDM) MIMO systems combined with Frequency Domain (FD) packet scheduling has not been studied so far. In this project, we investigate the distribution of Signal to Interference plus Noise Ratio (SINR) for multiuser spatial multiplexing OFDMA based downlink MIMO systems in combination with the base station based packet scheduler. The packet scheduler is used to exploit the available multiuser diversity in the time, frequency and spatial domains. In 3GPP Long Term Evolution (LTE) (also known as Evolved-UMTS Terrestrial Radio Access (E-UTRA or EUTRA)), Single Carrier (SC) Frequency Division Multiple Access (FDMA) has been adopted for uplink transmission, whereas the Orthogonal FDMA (OFDMA) signalling format has been exploited for the downlink transmission. SC-FDMA technique for uplink transmission has low Peak to Average Power Ratio (PAPR) property compared with competitive OFDMA technique. The SC-FDMA signal can be obtained by using Discrete Fourier Transform (DFT) spread OFDMA, where DFT is applied to convert time domain input data symbols to frequency domain before feeding them into an OFDMA modulator. For wide band wireless transmission systems, e.g., LTE OFDMA downlink and SC-FDMA uplink to simply scheduling task, several consecutive subcarriers are usually grouped together for scheduling. A basic scheduling unit is called a Resource Block (RB). The scheduler in Base Station (BS) may assign single or multiple RBs to a Mobile Station (MS). This project investigates space frequency scheduling for SC-FDMA based uplink multi-user MIMO system. We will also consider channel dependent scheduling algorithms for SC-FDMA based linearly precoded uplink MIMO systems
Supervisor: Branka Vucetic and Zihuai Lin
Cooperative Communications for Future Wireless Networks
The distributed nature of the wireless network provides unique opportunities for collaborative and distributed signal processing techniques that can potentially lead to significant energy saving and performance gain. Relaying protocols, distributed coding and collaborative signal processing strategies are key issues in design of cooperative wireless networks. At present there are many unsolved research problems in this field.
This project aims to develop cooperative communications techniques for multi-hop relay network, including optimization of distributed coding, joint channel and network coding design, development of new relaying protocols, cooperative transmission schemes, resource and power allocations and cross layer optimization. The developed techniques will be applied in wireless sensor networks for next generation cellular radio networks.
Supervisor: Yonghui Li and Branka Vucetic
Cooperative Transmission in MIMO Relay Broadcast Channels
Wireless multiuser communications are suffering from problems of reliability, coverage and spectrum efficiency. Relay broadcast is one of the promising techniques to solve these problems by exploiting the distributed spatial diversity arising from the relay mechanism and the local spatial diversity introduced by the multiple antennas.
The channel capacity of relay broadcast channels has been investigated in literature, which shows a significant improvement over the classical broadcast channels without relay. However, a practical transmission scheme is yet to be invented.
In this project, we design a low-complexity beamforming, relaying and combining scheme for MIMO relay broadcast channels. In the preliminary study, we consider the scenario where one base station (BS) transmits to two mobile stations (MSs), where one of the MSs with strong signal reception and/or processing power can help the other besides receiving its own data. The transmission vector space is partitioned into subspaces to accommodate the transmission from the BS to both MSs and the relaying between MSs. The zero forcing (ZF) criterion is used to avoid interferences among these transmissions. With multiple antennas at both the BS and MSs, and the channel state information (CSI) available (fully or partially) to the relevant parties, the subspace partitioning can be adjusted to optimise the overall system performance. The power allocation between users and relay can also be optimised to improve the performance further. Different levels of CSI availability will be investigated and reduced CSI scheme will be proposed such that the scheme can fit into both TDD and FDD systems. When more than two MSs are involved in the communication scenario, a relay selection algorithm will be developed in such a way the most effective MS is selected to act as the relay.
Supervisor: Branka Vucetic and Zhendong Zhou
