Yeqing Hu’s research while affiliated with Monash University (Australia) and other places

In this paper, we study the uplink performance in a 3D urban micro (3D-UMi) cell. The single-antenna users are distributed according to a 3D Poisson point process inside the cell. Each user has a probability to experience a line-of-sight (LoS) channel or a fading channel, and transmits to the multiantenna base station (BS) utilising fractional power control. The BS deploys a large 2D planar antenna array and performs 3D beamforming (BF) to receive the signals of all users in the cell sector. Under such a setting, we study the interference incurred by the co-channel users in the cell sector to a randomly located target user. In particular, we show that the interference incurred by the LoS interferers to a LoS target user is associated with the 3D BF antenna pattern. This type of interference is determined by the separation between the locations of the target user and interferer, and hence it is heavily dependent on the cell geometry. We exploit the massive MIMO regime and present a good approximation to model the LoS interference. We further resort to stochastic geometry to analyse the coverage probability and the rate per user in the cell.

In this paper, we study the uplink in a singlecell massive multiple-input-multiple-output (MIMO) system. The base station (BS) is equipped with three antenna arrays, each covering one-third of the cell area. Each antenna array comprises a large yet finite number of antennas. The single-antenna users are randomly and uniformly distributed in the cell, transmitting to the BS utilising full channel inversion power control. All users experience Rician fading. Receiver maximum-ratio-combining (MRC) is performed at the BS. Under such a setting, we focus on one cell sector and analyse the intra-sector interference in a realistic situation where the number of BS antennas is not extremely large compared with the user number. In particular, we show that due to the line-of-sight (LoS) component of the channel, the interference is partially determined by the angles of arrival (AoAs) of the signals.We approximate the LoS component interference by a Beta-mixture. The interference in Rician fading is then modelled as a non-central chi-square distribution with a random non-centrality parameter, corresponding to the LoS component. The approximate interference distribution can be used to compute signal-to-interference ratio (SIR) dependent metrics such as outage probability and average throughput.

In this paper, we study an uplink Poisson cellular network model, where the BSs and mobiles are located according to two independent Poisson processes with different densities. A Voronoi tessellation is formed based on the locations of BSs, dividing the network plane into cells. Each mobile communicates with the closest BS. Assuming an orthogonal channelised multiple access technique and a random channel reuse scheme, a BS randomly assigns its available channels to the users within its cell in a one-to-one manner. Under this setting, uplink coverage probability in a channel is studied. In addition, we introduce the concept of user spatial blocking, which occurs when a user has no access to any channel due to limited number of channels available in each cell. Approximate expressions for user spatial blocking probability and uplink coverage probability are derived in this paper.

In this paper, we consider a static Poisson cellular network, where the base stations (BSs) and mobiles are located according to two independent spatial Poisson processes. Voronoi cells are formed based on the locations of BSs. Mobiles falling into a Voronoi cell communicate with the BS in the same cell. Assuming a channelised multiple access technique, a BS randomly assigns available channels to the mobiles within the cell. Under such a setting, we introduce the concept of spatial blocking. Spatial blocking occurs when the number of users in a cell is greater than the number of channels available. We derive expressions for the spatial blocking probability under three random frequency reuse schemes: fixed-channel-available, random-channel-available and cell-dependent-channel-available.