Intercell Interference Measured in Urban Areas

2013 IEEE 77th Vehicular Technology Conference (VTC Spring)

Brylka

Krueger

et al. 2013

Self Cite

In this paper, we study the spatial structure of multiple-input multiple-output (MIMO) links in small urban macro-cells at 2.6 GHz. We resolve the double-directional structure of the radio channel. Also we compute common metrics used to characterize MIMO links, i.e. the structure of singular values and the resulting capacity. In a line-of-sight (LOS) link, we find that local scattering is not enough to create full-rank MIMO channels. Even behind a sector, we observe a low-rank channel. In a non-line-of-sight (NLOS) scenario, although we resolve several multi-paths with individual delay, direction of departure (DoD) and direction of arrival (DoA), the impact of local scattering is limited. Singular values indicate few more degrees of freedom for NLOS channels, but less than for a random matrix. We can model the spatial degrees of freedom in small cells better by assuming a random but small number of nearly specular paths feeding some local scattering widely spread in azimuth and elevation. Based on our results, we discuss modeling aspects and the value of large antenna arrays in mobile networks.

Section: B Singular Values and Capacitiessupporting

confidence: 44%

Spatial Degrees of Freedom in Small Cells: Measurements with Large Antenna Arrays

2013 IEEE 77th Vehicular Technology Conference (VTC Spring)

Brylka

Krueger

et al. 2013

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“…In previous channel measurement results [23], we observed that the transmitter correlation depends on the antenna spacing between the BSs. In Fig.…”

Section: Measurement Resultsmentioning

confidence: 72%

Field trials using coordinated multi-point transmission in the downlink

2010 IEEE 21st International Symposium on Personal, Indoor and Mobile Radio Communications Workshops

Forck

Jaeckel

et al. 2010

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Abstract-We report on field trials using CoMP transmission in the downlink of a mobile radio network. Two new features enable over-the-air CoMP transmission from physically separated base stations and terminals. These are distributed synchronization and a fast virtual local area network. Using VLAN tags, terminals feed back the multi-cell channel state information to their serving bases where it is multiplexed with shared data. Both are multicast to other cooperative base stations over the backhaul. In our trials, two terminals are served in two overlapping cells and placed in specific indoor, outdoor-to-indoor and outdoor scenarios. We have realized both intra-site as well as inter-site CoMP. While outage is indeed a big problem at the cell edge with full frequency reuse, with CoMP it is not observed anymore. Average throughput gains by factors 4 to 22 are observed when using CoMP compared to interference-limited transmission while between 27 and 78% of the isolated cell throughput is measured in both cells simultaneously.

“…At the receiver, we use a polarized uniform circular array (PUCA) with 8 patch elements [10]. Measurements with the same sounder but at other frequencies and with other antennas are also reported in [4,7,8,10]. Further details for this measurement campaign and additional results can be found in our earlier paper [4].…”

Section: Methodsmentioning

confidence: 99%

“…al. [3] while multicell delay spreads, fading correlations and the cell geometry are evaluated in our earlier paper [4].…”

Section: Introductionmentioning

confidence: 99%

Interference Limited MIMO Measurements

Jaeckel

Thiele

2010 IEEE 71st Vehicular Technology Conference

2010

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Abstract-We evaluate the interference limited spectral efficiency of a small cellular network using measurements with 3 sites at an ISD of 750 m. Each 3-sector site is equipped with cross-polarized panel antennas. We provide an efficient method to estimate the MIMO capacity from the measured data. We then compare the capacities of SISO and 2x2 MIMO with and without interference. At a fixed SNR of 10 dB, our cross-polarized interference free 2x2 setup achieves 5.7 bps/Hz which compares well to findings from Manhattan. For the best serving BS, the median 2x2 capacity including the received power and a reuse factor of 9 is 1.7 bps/Hz. This value increases to 3 bps/Hz when using frequency reuse 3 and 4.7 bps/Hz with full reuse.