| 1. |
- Almers, Peter, et al.
(författare)
-
Exercises
- 2005
-
Ingår i: Wireless Communications. - 9780470848883 - 047084888X - 0470848871 ; , s. 561-593
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 2. |
|
|
| 3. |
- Bernadó, Laura, et al.
(författare)
-
In-tunnel vehicular radio channel characterization
- 2011
-
Ingår i: [Host publication title missing]. - 1550-2252. - 9781424483327
-
Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedInside a tunnel, electromagnetic wave propagation differs strongly from the well understood "open-air" situation. The characterization of the tunnel environment is crucial for deploying vehicular communication systems. In this paper we evaluate vehicle-to-vehicle (V2V) radio channel measurements inside a tunnel. We estimate the time-varying root mean square (rms) delay and Doppler spreads, as well as the excess delay and the maximum Doppler dispersion. The fading process in V2V communications is inherently non-stationary. Hence, we characterize the stationarity time, for which we can consider the fading process to be wide sense stationary. We show that the spreads, excess delay, and maximum Doppler dispersion are larger on average when both vehicles are inside the tunnel compared to the "open-air" situation. The temporal evolution of the stationarity time is highly influenced by the strength of time-varying multipath components and the distance between vehicles. Furthermore, we show the good fit of the rms delay and Doppler spreads to a lognormal distribution, as well as for the stationarity time. From our analysis we can conclude that the IEEE 802.11p standard will be robust towards inter-symbol and inter-carrier interference inside a tunnel.
|
|
| 4. |
- Bernadó, Laura, et al.
(författare)
-
Multi-dimensional K-factor analysis for V2V radio channels in open sub-urban street crossings
- 2010
-
Ingår i: [Host publication title missing]. - 9781424480173 ; , s. 58-63
-
Konferensbidrag (refereegranskat)abstract
- In this paper we analyze the small-scale fading statistics for vehicle-to-vehicle (V2V) communications in a typical open sub-urban street crossing. The two cars approach the crossing from two different streets and the channel conditions vary from non line-of sight (NLOS) to line-of-sight (LOS). The small-scale fading of the first delay bin is Ricean distributed with a time-varying K-factor. The later delay bins are mostly Rayleigh distributed. The antenna arrays used for recording the multiple-input multiple-output channels are linear and consist of 4 elements with directional radiation patterns. We investigate the K-factor variation of the first delay bin in time, frequency, and space dimensions, where the measurement has a duration of 20 s, a bandwidth of 240 MHz, and 16 individual single-input single- output channels. We observe that the large/small K-factor values are not necessarily correlated with the received power. We show that the K-factor can not be assumed to be constant in any of the considered domains, not even in the frequency domain, as it has been always done for relative bandwidths up to 10%. The narrow- band K-factor for each frequency bin corroborates the need to consider its frequency variation. The antenna radiation patterns, and the illuminated objects by them at different time instances are the cause of these variations. We conclude that a multi- dimensional varying K-factor models the large-scale statistical behaviour more accurately than a constant K-factor.
|
|
| 5. |
- Koivunen, Jukka, et al.
(författare)
-
Dynamic multi-link indoor MIMO measurements at 5.3 GHz.
- 2007
-
Ingår i: Proc 2nd European Conference on Antennas and Propagation (EuCAP 2007).
-
Konferensbidrag (refereegranskat)abstract
- A dynamic multi-link MIMO channel indoor measurement campaign at 5.3 GHz is presented in this paper. The system setup is described and capacity with interference (with and without power control) results based on the dynamic multilink MIMO measurements are shown, and we experience a strong correlation between the relative capacity and SIR. Furthermore, an interference suppression metric is introduced and pathloss exponents and delay spreads are also presented, when moving from a typical office corridor to a large entrance hall at the premises of Lund University, Sweden.
|
|
| 6. |
- Kolmonen, Veli-Matti, et al.
(författare)
-
A dynamic dual-link wideband MIMO channel sounder for 5.3 GHz
- 2010
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456. ; 59:4, s. 873-883
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedIn this paper, we present and evaluate the performance of a dynamic dual-link wideband multiple-input-multiple-output ( MIMO) channel sounder. The channel sounder can simultaneously measure two wideband dual-polarized links, each with a MIMO matrix size of 30 x 30 and 30 x 32. Multi-link MIMO systems, including multiuser and cooperative MIMO, are essential parts of future high-throughput wireless local area networks and fourth-generation cellular systems. To fully understand such systems, the dynamic characteristics of multilink MIMO channels have to be measured. In this paper, we present a channel sounder that enables such measurements, including double-directional parameter estimation possibility for both links. The presented dual-link MIMO channel sounder does not suffer from the deficiencies of previous "virtual multiuser" measurement systems. Furthermore, system analysis and sample results from a measurement campaign with this channel sounder at 5.3 GHz in an indoor office environment are presented.
|
|
| 7. |
|
|
| 8. |
- Abbas, Taimoor, et al.
(författare)
-
Directional Analysis of Vehicle-to-Vehicle Propagation Channels
- 2011
-
Ingår i: IEEE Vehicular Technology Conference.
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a double directional analysis of vehicle-to-vehicle channel measurements conducted in three different traffic scenarios. Using a high-resolution algorithm, we derive channel parameters like Angle-of-Arrival (AOA), Angle-of-Departure (AOD), propagation delay and Doppler shift and identify underlying propagation mechanisms by combining these estimates with maps of the measurement sites. The results show that first-order reflections from a small number of interacting objects can account for a large part of the received signal in the absence of line-of-sight (LOS). This effect is especially pronounced in the two traffic scenarios where the road is not lined with buildings. We also found that the direction spread is low (and conversely that the antenna correlation is high) in such scenarios, which suggests that beam forming rather than diversity-based methods should be used if multiple antenna elements are used. The situation is reversed, however, in the third scenario, a narrow urban intersection, where a larger number of higher-order reflections is found to result in a higher direction spread.
|
|
| 9. |
- Abbas, Taimoor, et al.
(författare)
-
Directional Analysis of Vehicle-to-Vehicle Propagation in Different Traffic Environments
- 2010
-
Ingår i: [Host publication title missing].
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a double directional analysis of vehicle-to-vehicle channel measurements conducted in two different traffic environments. Using a high-resolution algorithm, we derive channel parameters like angle-of- arrival, angle-of-departure, propagation delay and Doppler’s spread and identify underlying propagation mechanisms by combining these estimates with maps of the measurement sites. The results show that single-bounce interaction with static objects is the dominating effect in the absence of line-of-sight, and that the contribution from other vehicles is small. We also find that in the absence of line-of-sight the direction spread at both sides of link is large which indicates possible diversity gain using multi-antenna arrangements.
|
|
| 10. |
- Alayon Glazunov, Andres, et al.
(författare)
-
A note on the Mean Effective Radiated Power and the Mean Effective Receiver Sensitivity of mobile handheld terminals
- 2008
-
Ingår i: 2008 IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting. ; , s. 1-4, s. 4471-4474
-
Konferensbidrag (refereegranskat)abstract
- In this paper we introduce the Mean Effective Radiated Power (MERP) and the Mean Effective Radiated Sensitivity (MERS) as alternative figures of merit of the uplink and downlink communication performance of wireless handheld terminals. We show how they are related to the Mean Effective Gain (MEG), the total radiated power (TRP) and total receiver sensitivity (TRS).
|
|
