Radio Channel Measurements With Relay Link at 780 MHz in an Outdoor to Indoor Propagation Environment

Transcription

1 Radio Channel Measurements With Relay Link at 780 MHz in an Outdoor to Indoor Propagation Environment Essi Suikkanen Centre for Wireless Communications University of Oulu

2 Outline Motivation for the Measurements Measurements Settings, antennas, location Post-processing of the Measurement Data Preliminary Results Route 4 BS to Relay All Routes Combined CWC Centre For Wireless Communications 2

3 Motivation for the Measurements Provide measurement data for the WINNER+ project to extend WINNER and IMT-A channel models down to MHz. To get actual measurement data of a scenario where relay assisted transmission is used. How much benefit can be gained from the use of a relay? Combat shadowing and path loss g p Potential to extend coverage and increase spectral efficiency

4 Measurements Measurement settings: Center frequency Transmit power Bandwidth 780 MHz +25 dbm 50 MHz Chip rate 25 Mcps Sampling frequency Code length 50 MHz 4095 chips Number of Tx antenna elements 6 Number of Rx antenna elements CWC Centre For Wireless Communications 4

5 Measurements Used antennas: Antenna designation Frequency / Bandwidth Radiation Gain Discone 700 MHz / 200 MHz ±180 Azimuth 90 Elevation ~ 3 db Antenna type Uniform circular array, 6 discone elements Polarization Vertical

6 Measurements Routes for measurements with mobility BS-MS and relay-ms measurements Figures 1 and 2 show measured routes (pink lines), base station location (light blue dot) and relay location (green dot). The direction of the first antenna element is marked with red arrow. The location of the relay is not shown in Figure 2 but it is the same as in the Figure 1. The height of the BS was at 23 metres and the height of the relay was 14 metres. Height of the MS antenna was 1.5 metres.

7 Measurements Figure 1: Routes 1-4. Figure 2: Route 5 and two spot measurements.

8 Measurements Routes for static measurements BS-relay measurements Figure 3 depicts the locations of the relays (green dots) and the base station (light blue dot). The direction of the first antenna element is marked with red arrow. Height of the BS was 23 metres and the height of the relay was 6-14 metres.

9 Measurements 42 m 59 m Figure 3: Location of the base station and the relays.

10 Measurements Relay 1 Relay 4 Figure 4: View from the BS antenna to the lifter where the relay R1 was located. Also the location of the R4 is shown.

11 Measurements BS Figure 5: View from the relay antenna to the BS antenna.

12 Post-processing and Analysis For post-processing and analysis we use Matlab and ISIS The ISIS (Initialization and Search Improved SAGE) is Matlab based super-resolution option for post-processing and it provides multi-dimensional estimates of the wave parameters. It is based on the SAGE (Space-Alternating Generalized Expectation-Maximization) maximum likelihood algorithm. From the static measurements (BS-relay) the first 100 cycles of the measurement data are analyzed. From the measurements where the MS was moving, the whole route is analyzed. y Noise threshold was set to 20 db below the strongest tap for all measured impulse responses.

13 Preliminary Results Route 4 Preliminary results for route 4 In the map below are shown the distances between the BS, relay and MS m 59 m m The beginning of route 4

14 Preliminary Results Route 4 1 Prob bability of RM MS delay < Ab bscissa Mean: ns Std: ns Mean: ns Std: ns BS to MS R1 to MS - The walls in the beginning of the route are glass. - Obstructed LOS from the relay to the MS. - NLOS from the BS to the MS RMS delay [ns] Figure 6. Cdfs of RMS delay spread for route 4.

15 Preliminary Results Route Approximately 20 db difference. 90 oss [db] Pathl BS to MS R1 to MS Normalized snap shot Figure 7. Path loss per cycle for route 4.

16 Preliminary Results Route 4 1 Proba ability of shad dow fading < Abscissa Mean: db Std: 2.78 db Mean: 0.00 db Std: 2.18 db - Almost equal standard deviations for both cases. 0.1 BS to MS R1 to MS Shadow fading [db] Figure 8. Cdfs of shadow fading for route 4.

17 Preliminary Results Route BS to MS - In the relay-ms case R1 to MS capacity drops when the MS moves in NLOS area. [bits/s/hz] Capacity [ Normalized snap shot Figure 9. Capacity per cycle for route 4.

18 Preliminary Results BS to Relay MS delay < Abscissa Pro obability of R Mean: 8.76 ns Std: 2.36 ns Mean: 8.96 ns Std: 0.03 ns Mean: 8.50 ns Std: 0.16 ns R1 at 14 m R1 at 10 m R1 at 6 m R4 at 14 m Mean: ns Std: 1.68 ns RMS delay [ns] Figure 14. Cdfs of RMS delay spread from BS to R1 at different heights and BS to R4 at the highest point.

19 Preliminary Results BS to Relay Pathl oss [db] R1 at 14 m R1 at 10 m R1 at 6 m R4 at 14 m - The highest R1 location is the best in terms of path loss. - Nevertheless, only 3.5 db difference between the highest R1 and the lowest R Normalized snap shot Figure 15. Path loss per cycle from BS to R1 at different heights ht and BS to R4 at the highest point.

20 Preliminary Results - BS to Relay Pro obability of ca apacity < Abs scissa Mean: bits/s/hz Std: 0.28 bits/s/hz Mean: bits/s/hz Std: 0.35 bits/s/hz Mean: bits/s/hz Std: 0.17 bits/s/hz R1 at 14 m R1 at 10 m R1 at 6 m R4 at 14 m Mean: bits/s/hz Std: 0.44 bits/s/hz - The lowest R1 location as good as the R4. - Approximately 6 bits/s/hz difference between the highest R1 and the R Capacity [bits/s/hz] Figure 16. Cdfs of capacity from BS to R1 at different heights and BS to R4 at the highest point.

21 Preliminary Results All Routes Combined a) b) Figure 17. Cdfs of RMS delay spread from BS to MS (a) and relay to MS (b) for all measured routes.

22 Preliminary Results All Routes Combined a) b) Figure 18. Path loss curves from BS to MS (a) and relay to MS (b) for all measured routes.

23 Preliminary Results All Routes Combined a) b) Figure 20. Cdfs of capacity from BS to MS (a) and relay to MS (b) for all measured routes.