Page 62 - ITU Journal Future and evolving technologies Volume 2 (2021), Issue 6 – Wireless communication systems in beyond 5G era

ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 6

(b) UE antenna from (155, −960,3) to (155,960,3). It can be seen
that in the conventional method (w/o RS), in most
In this paper, UE = 72 antenna beams are UE positions, mmWave communications are not
modeled by ideal sector antenna covering all upper
hemi-sphere [23]. possible due to the blockage effects of buildings. In
addition, even at positions where the channel
(c) RS antenna capacity is obtained, the number of the streams is
All RS antennas are assumed to have ideal beam only one, indicating that no reflected wave can be
control and always direct to the target antenna with obtained and MIMO transmission is not possible. On
the maximum directivity gain. The sinc function is the other hand, in the proposed method, channel
used as the antenna directivity pattern of RSs [24]. capacities of about 5Gbps or more is obtained
regardless of UE position, and number of streams is
4.2 Results of numerical analysis greatly improved, indicating that MIMO

Based on simulation configurations explained transmission is possible. At positions where
above, system performance of the proposed channel capacity was able to be obtained by LOS
massive analog relay MIMO for mmWave path, i.e., y UE = −30, 0, 30 m, further increase on
communications is evaluated by numerical channel capacity can be obtained.
simulations. Fig. 11 shows dependency of channel capacity on
the available number of RSs. To evaluate capacities
4.2.1 One-dimensional arrangement model
with a different number of RSs, RSs are turned on in
For the one-dimensional case, Fig. 9 and Fig. 10 order from #1 to #64 as shown in Fig. 7. Evaluations
show channel capacity and number of streams
plotted every 15 m when the UE moves straight

Fig. 9 – Position of UE and channel capacity in
one-dimensional arrangement model
Fig. 7 – One-dimensional arrangement model

Fig. 10 – Position of UE and number of streams in one-
Fig. 8 – Two-dimensional arrangement model dimensional arrangement model

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