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In this paper, we propose a channel estimation scheme for a long term evolution-advanced (LTE-A) downlink system. The proposed scheme uses the fast Fourier transform (FFT) interpolation scheme for the user moving at a high speed. The FFT interpolation scheme converts the channel frequency response obtained from the least square or minimum mean square error channel estimation scheme to a time-domain channel impulse response by using the inverse FFT (IFFT). After windowing the channel response in the time domain, the channel frequency response can be obtained using the FFT. We performed a system-level simulation based on the 20 MHz bandwidth of the 3rd Generation Partnership Project LTE-A downlink system. Simulation results show that the proposed channel estimation scheme can improve the signal-to-noise-plus-interference ratio, as well as the throughput and spectral efficiency, of a conventional system. [ABSTRACT FROM AUTHOR]

Recently, 3rd Generation Partnership Project (3GPP) has developed a network-assisted interference cancellation and suppression scheme to reduce the effect of interference. In this paper, we propose an advanced receiver based on soft decision to reduce the interference from the neighbor cells. The proposed receiver can suppress and cancel the interference by calculating the unbiased estimation value of the interference signal using the minimum mean square error or the interference rejection combining receiver. The interference signal is updated using soft information expressed by the log-likelihood ratio. We perform the system-level simulation based on 20 MHz bandwidth of a 3GPP LTE-Advanced sidelink system. The simulation results show that the proposed receiver can improve the signal-to-noise-plus-interference ratio, throughput, and spectral efficiency of a conventional system. [ABSTRACT FROM AUTHOR]

Recently, the 3rd Generation Partnership Project (3GPP) has developed a sidehaul system to cope with rapidly increasing mobile data traffic. Nevertheless, numerous challenging technical problems remain. One of the major problems is interference management between small cells. In this paper, we propose a novel hybrid receiver for full suspension cancellation to reduce the interference from neighboring cells in the sidehaul system. The proposed receiver can cancel and suppress interference by integrating the interference rejection combining technique with successive interference cancellation. We perform a simulation based on the 20-MHz bandwidth of the 3GPP LTE-Advanced technology. Simulation results show that the proposed receiver can achieve a lower error rate and a higher throughput compared to conventional receivers. [ABSTRACT FROM AUTHOR]

A heterogeneous network (HetNet) based on the long-term evolution advanced standard has been developed to improve the system performance; in this HetNet, macrocells and low-power nodes, such as picocells, coexist. Further, cell range expansion has been introduced to encourage data offloading in a HetNet. In this paper, we propose a cell selection scheme based on the signal-to-interference-plus-noise ratio to achieve an optimal offloading effect. We also propose a resource allocation scheme in the frequency and time domains, to reduce interference in a HetNet. In the frequency domain, the macrocells allocate a frequency band by using soft frequency reuse, and the picocells choose the sub-bands that are not used in the macrocell sector, to avoid interference. In addition, we found that it was difficult to allocate a limited frequency resource. Therefore, the cross-tier interference can be managed by using an almost blank subframe (ABS) with a flexible ABS ratio, to improve spectrum efficiency in the time domain. The simulation results show that the proposed schemes can improve the spectrum efficiency of both the macro-user equipment and the pico-user equipment, as well as improve the overall UE performance. [ABSTRACT FROM AUTHOR]