Capacity enhancement using MIMO antenna arrays in realistic macro-cellular urban environment

In MIMO systems the antenna array configuration in the BS and MS has a large influence on the available channel capacity. In this paper, we first introduce a new Frequency Selective (FS) MIMO framework for macro-cells in a realistic urban environment. The MIMO channel is built over a previously developed directional channel model, which considers the terrain and clutter information in the cluster, line-of-sight and link loss calculations. Next, MIMO configuration characteristics are investigated in order to maximize capacity, mainly the number of antennas, inter-antenna spacing and SNR impact. Channel and capacity simulation results are presented for the city of Lisbon, Portugal, using different antenna configurations. Two power allocations schemes are considered, uniform distribution and FS spatial water-filling. The results suggest optimized MIMO configurations, considering the antenna array size limitations, specially at the MS side

Characterization and Enhancement of Antenna System Performance in Compact MIMO Terminals

Co-band multiple-antenna implementation in compact user terminals is necessary for harvesting the full potential of diversity and multiple-input multiple-output (MIMO) technology in cellular communication systems. The recent worldwide deployment of Long Term Evolution (LTE), which requires the use of MIMO technology in the downlink, adds to the urgency of achieving both practical and optimal multiple-antenna systems in user terminals. Contrary to conventional understanding, an optimal multiple-antenna implementation does not only involve the design and placement of antenna elements in the terminals, but extends beyond the antenna elements and common antenna parameters to comprise interactions with the near field user and the propagation environment. Moreover, these interactions are non-static, which implies that the multiple-antenna system must adapt to the prevailing overall communication channel in order to assure the highest performance gains. This doctoral thesis aims to address several key issues in optimal multiple-antenna system design for compact multi-band MIMO terminals, with the first half (Papers I to III) focusing on the performance characterization of such terminals in the presence of user interaction and propagation channel, under the challenging constraint that the terminals are compact. The second half of the thesis (Papers IV to VI) considers two performance enhancement approaches suitable for compact MIMO terminals in realistic usage conditions. In particular, the potential benefits of harmonizing compact multiple-antenna systems with the propagation channel and user influence are determined with respect to reconfigurability in antenna patterns and impedance matching circuits. In Paper I, the diversity performance of internal multiple antennas with multi-band coverage in a mock-up with the size of a typical mobile handset is investigated in different user interaction scenarios. For comparison, a second mock-up with only one multi-band antenna is also evaluated in the same user cases. An ideal uniform propagation environment is assumed. The performance at frequency bands below and above 1 GHz are presented and analyzed in detail. Paper II extends the study in Paper I by evaluating the single-input multiple-output (SIMO) and MIMO capacity performance of the same antenna prototypes under the same user interaction scenarios and propagation environment. In Paper III, the impacts of gain imbalance and antenna separation on the throughput performance of a dual-dipole configuration are studied at frequencies below and above 1 GHz in a repeatable dynamic multi-path environment, using a live HSPA network. Since the compactness of a user terminal has implications on the antenna separation and gain imbalance of the multiple antennas, the focus is to gain knowledge on how these two factors affect the end user experience in practice. In Paper IV, three simple dual-antenna topologies implemented in compact smart phone prototypes of identical form factors are evaluated in MIMO channel measurements in noise-limited and interference-limited urban scenarios. Each dual-antenna topology is intentionally designed to provide a distinct set of antenna patterns. The goal is to investigate the potential of antenna system design as one of the key performance differentiators in real terminal implementations. Paper V extends the work in Paper IV by introducing user interaction to the same MIMO channel measurement setup. Furthermore, the focus of this paper is on the evaluation of both the average and local channel performances and their potential enhancements. Finally, Paper VI ascertains the potential capacity gains of applying uncoupled adaptive matching to a compact dual-antenna terminal in an indoor office environment, under a realistic user scenario. The performance gains are evaluated by means of extensive MIMO channel measurements at frequency bands below and above 1 GHz

D3.2 First performance results for multi -node/multi -antenna transmission technologies

This deliverable describes the current results of the multi-node/multi-antenna technologies investigated within METIS and analyses the interactions within and outside Work Package 3. Furthermore, it identifies the most promising technologies based on the current state of obtained results. This document provides a brief overview of the results in its first part. The second part, namely the Appendix, further details the results, describes the simulation alignment efforts conducted in the Work Package and the interaction of the Test Cases. The results described here show that the investigations conducted in Work Package 3 are maturing resulting in valuable innovative solutions for future 5G systems.Fantini. R.; Santos, A.; De Carvalho, E.; Rajatheva, N.; Popovski, P.; Baracca, P.; Aziz, D.... (2014). D3.2 First performance results for multi -node/multi -antenna transmission technologies. http://hdl.handle.net/10251/7675