INTERNATIONAL TELECOMMUNICATION UNION
RADIOCOMMUNICATION
STUDY GROUPS
UK SG3
CP70rev1
Document 3K/UK16-E
22 March 2002
English only
United Kingdom
PROPOSED REVISION TO RECOMMENDATION ITU-R P. 1411-1
Route dependence of wideband channel characteristics
1. Introduction
Wideband channel characterisation is usually obtained from small-scale channel
parameters such as the power delay profile, its first and second central moments and
interval width. These are obtained from measurements over areas on the order of a few
wavelengths. Subsequently, large-scale or global characterisation is obtained from
cumulative distributions of these parameters over a large area. However, to characterise
the channel for both pedestrian and vehicular users, wideband measurements are usually
carried out using a trolley or a van, respectively.
In this event, a pedestrian user is only likely to cover a few hundred meters along a
particular route, whereas a vehicular user can cover a wide area. To distinguish between
both types of areas medium scale area is introduced here as the area that would be
covered by a pedestrian or a route. Large scale refers to the sum of a number of routes
whether covered by a trolley or a van.
2. Measurement results
Wideband measurements over the two UMTS frequency division duplex bands were
carried out with a dual frequency chirp sounder designed and implemented in the UK [1].
Measurements over the two 60 MHz bands were analysed on a route basis (medium
scale) and the results from all the routes were subsequently accumulated to obtain largescale characteristion [2]. Figure 1 shows examples of three routes covered with the
trolley in the city centre of Manchester. Route C covered tunnels and a train station with
all the paths being nearly radial with respect to the transmitter. Route D covered both
radial and circumferential streets and route W1 was mainly circumferential. All the
routes covered with the trolley were in an area within 1.6 km from the transmitter and
each route covered a range of a few hundred meters. The transmit antenna was located
on top of a 46-m building and the receive antenna was either at 1.7 m for the trolley
measurements or 2.5 m for the van measurements. Both antennas were vertically
polarised and omni-directional and the effective radiated power was 34 dBm. The overall
number of locations surveyed was 581 locations.
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Figures 2 and 3 show the concatenated power delay profiles for routes C and W1 for the
two frequency bands. The power delay profiles are displayed as a function of received
RF power. The figure shows the dependence of the delay spread on the route. This is
also seen from figure 4, which shows the delay interval for 15-dB threshold for the three
routes for both the uplink and downlink. Figure 5 shows the corresponding large-scale
cumulative distribution from all the trolley routes and from the van route. The route
dependence of the channel parameters is evident from the two figures and the effect of
the overall data pool can also be seen.
References:
1. Salous, S., and Gokalp, H., Dual frequency sounder for UMTS frequency division
duplex channels, accepted for publication in the IEE Proceedings Communications.
2. Salous, S., Analysis of route and frequency dependence of wideband channel
characteristics, URSI-F symposium, February, 2002.
D
W1
C
Transmitter
Figure 1. Map of urban measurements. Routes: W1, D, C
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Uplink
Downlink
Figure 2. Power delay profiles for route C.
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Figure 3. Power delay profiles for route W1.
s
Figure 4. Cumulative distribution for the three routes of figures 1.
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s
Figure 5. Cumulative distribution for all the trolley routes and the van route.
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ANNEX
Proposed Revision to Recommendation ITU-R P.1411-1
Section 6, Multipath models
After line 2 ending with “ITU-R.1407” Add the following paragraph
“The statistics of the delay spread in an urban high-rise environment for small macrocells (as defined in Table 3), have been found to be strongly related to the route of the
measurement. This gives rise to three different classifications: small-scale (single
location over a few wavelengths), medium scale (short route of a few hundred meters)
and large scale (a large area which includes a number of varied routes and can extend to
ranges from a few hundred meters to a few km’s). Significant differences can be
observed between the medium scale characterisation particularly between radial and
circumferential routes. For large scale characterisation a large number of locations
should be surveyed in the measurements to obtain an unbiased estimate.”