This paper proposes a cellular network exploiting millimeter-wave (mmWave) and ultra-densified base stations (BSs) to achieve the far-reaching 5G aim in downlink average rate. The mmWave overlaid network however incurs a pitfall that its ample data rate is only applicable for downlink transmissions due to the implementation difficulty at mobile users, leading to an immense difference between up...

In this paper, we propose a new channel estimation scheme for TDD/FDD massive MIMO systems by reconstructing uplink/downlink channel covariance matrices (CCMs) with the aid of array signal processing techniques. Specifically, the angle information and power angular spectrum (PAS) of each multi-path channel is extracted from the instantaneous uplink channel state information (CSI). Then, the upl...

In this paper, we study the sensitivity of uplink and downlink MC-DS-CDMA to carrier frequency offsets, assuming orthogonal spreading sequences. For both uplink and downlink MC-DS-CDMA, we show that the performance rapidly degrades for an increasing ratio of maximum frequency offset to carrier spacing. We point out that the degradation in the uplink is larger than in the downlink, because only ...

Downlink data products in Mars rover missions need to be associated with their uplink commanded target locations and the uplink commands that produced them. A system for automatically associating downlink data products with uplink commands and targets has been developed and used in a terrestrial rover field test. HTML reports viewable in a browser are automatically generated to relate downlink ...

We investigate the congruence of the directional properties of uplink (UL) and downlink (DL) as seen from the base station in WCDMA of UMTS by means of spatial channel measurements. Our study illustrates that the directional properties of the mobile radio channel are strongly correlated in uplink and downlink radio channels. Therefore, the utilization of spatial information derived during uplin...

The performance of a downlink power control model, based on a n-th power distance law, is evaluated for high altitude platform station (HAPS) W-CDMA systems. The downlink capacity using this model is compared with the uplink capacity. It is shown that the uplink capacity is higher than the downlink capacity.

In many scenarios, low latency wireless communication assumes two-way connection, such that the node that receives information can swiftly send acknowledgment or other response. In this paper, we address the problem of low latency two-way communication and address it through proposal of a base station (BS) cooperation scheme. The scheme is based on downlink (DL) and uplink (UL) decoupled access...

This paper considers the max-min weighted signal-to-interference-plus-noise ratio (SINR) problem subject to multiple weighted-sum power constraints, where the weights can represent relative power costs of serving different users. First, we study the power control problem. We apply nonlinear Perron-Frobenius theory to derive closed-form expressions for the optimal value and solution and an itera...

1 good. The conventional handover scheme is performed considering only downlink information. However uplink and downlink signal qualities can be asymmetric in Time Division Duplexing (TDD)/Orthogonal Frequency Division Multiple Access (OFDMA) systems like IEEE 802.16e systems. Therefore conventional handover schemes based on the downlink signal could degrade the uplink quality of service (QoS)....

This paper describes the effects of traffic distributions on uplink and downlink communications qualities in CDMA cellular systems. Many researches have been done from the viewpoint of the system capacity under ideal conditions in both uplink and downlink. However, there are few studies regarding traffic distributions that concurrently affect the uplink and downlink quality. The characteristics...