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In this paper, we analyze the system performance under HWIs and propose an approach to address the problem.
The system performance is related to the signal-to-interference-plus-noise ratio (SINR), where the interference consists of multiuser interference, and the noise originates from the HWIs at the BS and user terminals.
where p is the power assigned to each user; [|E[[h.sup.H.sub.k] [[THETA].sup.H.sub.k](t)[f.sub.k]]|.sup.2]reflects the gain of the desired signal at the user; E[[|[h.sup.H.sub.k] [[THETA].sup.H.sub.k](t)[f.sub.k]|.sup.2]] reflects the multiuser interference caused by the signal intended for the [k.sup.th] user; E [|[h.sup.H.sub.k][[THETA].sup.H.sub.k](t)[[gamma].sup.BS.sub.t] [[THETA].sub.k](t)[h.sub.k]|] originates from the HWIs at the BS, that is, the distortion noise [[eta].sup.BS.sub.t];E[[v.sup.UT.sub.k,r](t)] originates from the HWIs at the [k.sup.th] user terminal, that is, the distortion noise [[eta].sup.UT.sub.r,k]; and [[zeta].sup.DL] is the downlink amplified thermal noise.
More insight about the impact of the HWIs and the number of local oscillators is provided by simulation results in Section 5.
The analysis is similar to the one under user data rate, and more insight about the impact of HWIs and the number of local oscillators on the required downlink transmit power is also provided in Section 5.
In order to evaluate the impact of the transceiver hardware impairments on the performance of the downlink system, we first plotted the achievable user data rate against the number of base station antennas for CLO and SLOs configurations and for the case where it is assumed that there is no HWIs or other performance limiting factors and the CSI is perfect.
This can be justified by the fact that as the number of BS antennas grows large, the detrimental effect of HWIs at the BS vanishes almost completely because the noises are spread in arbitrary directions, and the spatial resolution of the array increases and enables exact transmit beamforming for the useful signal.
In the following figures, only HWIs cases are investigated.
In this subsection, we investigate on the effect of the cell radius reduction on the HWIs and hence on the user data rate, and required transmit power.
These universities, in line with other HWIs, employed black Vice Chancellors.
In sum, the inward looking universities such as the older HBIs and the Afrikaner HWIs propagate the concept of African languages as opposed to the establishment of centres or departments dealing specifically with the study of Africa as it pertains in Europe and other parts of the world.
Much as there existed two version of the HWI's, two categories of the HBIs existed; the ones operating within the Republic of South Africa, and the others operating within their respective homelands.
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