| 1. |
- Bin Redhwan, Sakib, et al.
(författare)
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Evaluation of the effect of base station antenna polarization on the performance of CoMP transmission techniques based on synchronous multi-link measurements
- 2016
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Ingår i: 2016 IEEE 27th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications - (PIMRC). - 9781509032549 - 9781509032556
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Konferensbidrag (refereegranskat)abstract
- In this paper, the effect of polarization on the downlink achievable sum-rate of multi-user Cooperative Multi-Point (CoMP) systems is studied using synchronous multi-link channel measurements with two different antenna arrangements. In the first setup, four dual-polarized antenna patches with inter-patch distance varied from half wavelength to 8 m are considered at the base station (BS). In the second setup, two BSs located 60 m apart are used, each is provided with dual-polarized antennas spaced half a wavelength apart. Based on the BS antenna element selection, scenarios with different antenna polarizations at the BSs are considered. We consider four virtual users each is equipped with two antennas (V and H-polarized) with half-wavelength inter-element distance. The users are equally spaced with inter-user distance of about 0.5 m and moving in different routes. For each setup, the 8 × 4 MIMO multi-user channels are used to evaluate the achievable sum-rate of the system, where the minimum mean square error (MMSE) beamforming at both the BS and the mobile station (MS) is used. It is found that the performance improvement gained from using dual-polarized antennas at the BS vanishes if the BS antenna elements are distributed over large distance (i.e., having a large antenna array aperture). However, in the measured environment, for the case of having two BSs each of which is provided with co-located antennas, using dual-polarized antennas provide about 40% improvement in the ergodic sum-rate compared to using single-polarized antennas.
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| 2. |
- Flordelis, Jose, et al.
(författare)
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Exploiting antenna correlation in measured massive MIMO channels
- 2016
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Ingår i: 2016 IEEE 27th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, PIMRC 2016. - 9781509032549
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Konferensbidrag (refereegranskat)abstract
- We investigate antenna correlation of an M-antenna massive multiple-input multiple-output (MIMO) setup with the purpose of obtaining a low-rank representation of the instantaneous massive MIMO channel. Low-rank representation bases using short-term and long-term antenna correlation statistics are defined, and their performance is evaluated with data sets obtained from channel measurements in both indoor and outdoor environments at 2.6 GHz. Our results indicate that the short-term bases can capture a larger amount of the channel energy compared to the long-term ones, but they have a limited timespan, one coherence time or less. On the other hand, the long-term bases are stable over time-spans of a few seconds. Hence, they can be obtained relatively easily. We also investigate a rank-p vector-scalar LMMSE channel estimator that exploits antenna correlation. Our results show that the investigated estimator can achieve a performance similar to that of full-rank LMMSE at a (2p + 1)/M times lower cost. The investigated estimator may be used in conjunction with estimators that exploit correlation in the frequency and time domains or, alternatively, in situations in which these estimators cannot be used, e.g., when pilot separation is larger than the channel coherence bandwidth or time.
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| 3. |
- Papaioannou, Panagiotis, et al.
(författare)
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Performance evaluation of CoMP transmission schemes using measurements versus the COST 2100 channel model
- 2016
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Ingår i: 2016 IEEE 27th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, PIMRC 2016. - 9781509032549
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Konferensbidrag (refereegranskat)abstract
- Coordinated Multi Point (CoMP) transmission and reception techniques are used in order to improve the performance of single or multiple cells in wireless systems. A system using CoMP techniques is capable of jointly optimizing its transmission and/or reception and, hence, achieving higher performance. In this work, performance evaluation of three CoMP techniques are performed based on simulations using the COST 2100 channel model and also based on measured channels collected from a synchronous multi-link measurement campaign at Lund University. The contribution of this work is twofold. First, the performance evaluation of different CoMP transmission techniques, namely, the Joint Processing, the Partial Joint Processing and the Coordinated Beamforming, are presented. Second, the capability of the COST 2100 model in predicting the relative performance of different CoMP techniques is assessed. It was found that the COST 2100 model is capable of estimating the relative performance of the studied CoMP schemes well. Moreover, detailed comparison highlighting the agreements and discrepancies between the performance results based on the measured channels and those based on the COST 2100 model are reported.
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| 4. |
- Salous, Sana, et al.
(författare)
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Urban Radio Access Networks
- 2016
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Ingår i: Cooperative Radio Communications for Green Smart Environments. - 9788793379152 - 9788793379145 ; 47, s. 17-70
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The increase in demand for high-data rates on the move in the complex urbanenvironment requires either the allocation of new spectrum such as availablecontiguous spectrum in the mm-wave band or the use of novel configurationssuch as the application of massive multiple-input multiple-output (MIMO)technology. To enable the design of efficient wireless networks, an understandingof the propagation phenomena in the diverse urban environments isfundamental. In this chapter, we present results of studies related to fourthgeneration (4G) and future 5G radio systems both outdoor and outdoor-toindoor.Classifications include rural and highway, BS to pedestrian users,vehicular-to-vehicular, vehicular-to-infrastructure, container terminals, vegetation,and high-speed mobility such as trains. Results for path loss (PL)and shadow fading are presented from various studies of stochastic anddeterministic channel models based in outdoor, indoor-to-outdoor, hotspots,vehicular, and train environments. Relay stations and the impact of antennaplacement in vehicles, antenna terminal height, and the presence of pedestriansare discussed. Results of angular spread and rms delay spread of widebandchannels are presented for the frequency bands below 6 GHz allocated for4G networks, and preliminary results in the mm-wave band, envisaged for5G networks, including prediction of the impact of rain. To facilitate thesimulation of radio networks in urban environments the Hannover Scenariois proposed to give a common simulation environment.
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