Uplink User Capacity in a CDMA System with Hotspot Microcells: Effects of Finite Transmit Power and Dispersion

This paper examines the uplink user capacity in a two-tier code division multiple access (CDMA) system with hotspot microcells when user terminal power is limited and the wireless channel is finitely-dispersive. A finitely-dispersive channel causes variable fading of the signal power at the output of the RAKE receiver. First, a two-cell system composed of one macrocell and one embedded microcell is studied and analytical methods are developed to estimate the user capacity as a function of a dimensionless parameter that depends on the transmit power constraint and cell radius. Next, novel analytical methods are developed to study the effect of variable fading, both with and without transmit power constraints. Finally, the analytical methods are extended to estimate uplink user capacity for multicell CDMA systems, composed of multiple macrocells and multiple embedded microcells. In all cases, the analysis-based estimates are compared with and confirmed by simulation results.Comment: To appear in IEEE Transactions on Wireless Communication

Multipath effect on the WCDMA uplink capacity of highways cigar-shaped microcells with users within cars and buses

The final publication is available at Springer via http://dx.doi.org/10.1007/s11277-012-0900-3In this work, the effect of the multipath on the capacity and the interference statistics of the sectors of the highways cigar-shaped W-CDMA microcells is studied. A model of five microcells is used to analyze the uplink. The capacity and the interference statistics of the microcell are studied for different antenna sidelobe levels and different sector ranges. In the study, imperfect power control and limited transmitted power are assumed. Users are assumed to be within equally spaced buses and cars. The uplink capacity of the sector is studied assuming three types of services, namely, voice, 3G data and 3.75G data (representing the High Speed Uplink Packet Access). It is shown that, the sector uplink capacity depends on the buses and cars density within the sector. The capacity is also given as a function of the number of buses and cars within the sector

WCDMA multiclass downlink capacity and interference statistics of cigar-shaped microcells in highways

The final publication is available at Springer via http://dx.doi.org/10.1007/s11277-013-1048-5In this paper, the multiclass downlink capacity and the interference statistics of the sectors of a cigar-shaped microcells using wideband code-division multiple-access with soft handover mode are analyzed. The two-slope propagation model with log-normal shadowing is used in the analysis where a model of 8 cigar-shaped microcells is utilized. The performance of the downlink is studied for different [sector range R, standard deviation of the shadowing (σ1 and σ2) and propagation exponents (s1 and s2)]. It is found that increasing the sector range from 500 to 1,000 m will increase the sector downlink capacity. Also, it is found that increasing the value of the propagation parameters (σ1 and σ2) will reduce the downlink sector capacity. It is noticed that, the effect of changing the propagation exponent s1 is null while increasing the propagation exponent s2 will increase the downlink capacit

WCDMA downlink capacity of cigar-shaped microcells using soft hand-over with SIR-based power control for over-ground train service

In this paper, the downlink sector capacity of a cigar-shaped microcells using wideband code-division multiple-access (WCDMA) with soft hand-over (SHO) mode is analyzed. The two-slope propagation loss with log-normal shadowing is used in the analysis where a model of eight cigar-shaped microcells is utilized to calculate the downlink sector capacity. The performance of the downlink is studied for different sector radii, standard deviations of the shadowing and propagation exponents. It is found that, for a sector range higher than 940 m, increasing the sector range will reduce the downlink sector capacity. Also it is found that increasing the value of the propagation parameters will reduce the downlink sector capacity. In many cases, the downlink sector capacity will be code limited since the theoretical downlink sector capacity is higher than the number of codes assigned to each sector. The high theoretical downlink sector capacity is due to the low value (0.06–0.1) of the WCDMA orthogonality factor of rural zone microcells

WCDMA Uplink Capacity of a Long Tunnel Cigar-shaped Microcells for Underground Train Service

In this paper, the capacity and the interference statistics of the sectors of the cigar-shaped WCDMA microcells are studied using the hybrid model of propagation. A model of nine microcells in a metro tunnel is used to analyze the uplink capacity and the interference statistics. The capacity and the interference statistics of the microcells in metro tunnels are studied in this work for different propagation parameters, antenna side lobe levels, sector ranges and bends losses

The Capacity and Interference Statistics of High Car Traffic W-CDMA Street Cross-Shaped Micro-Cells (Uplink Analysis),

Since interference is related to the capacity and performance of W-CDMA system, it is necessary to investigate the interference characteristics (the mean value and the variance). Thus, the uplink capacity and the interference statistics of the sectors of the cross-shaped W-CDMA microcell have been analyzed using geometry with 17 microcells. A single slope propagation model with a lognormal shadowing factor has been used in the analysis. The cells have been assumed to exist in city streets with high car traffic. The capacity and the interference statistics of the sectors have been studied for different sector ranges, and different side-lobe level. The results show that the capacity increases with the increment of the sector range and with the reduction of the side-lobe level of the antennas used

WCDMA uplink capacity of highways cigar-shaped microcells with incorporated HSUPA service

The final publication is available at Springer via http://dx.doi.org/10.1007/s11277-011-0229-3The multi-service (voice, data and HSUPA) uplink capacity and the interference statistics of the sectors of the cigar-shaped WCDMA microcell are studied using a model of 5 highway microcells. The two-slope propagation loss model with lognormal shadowing is used in the analysis. It is concluded that the voice and data service are significantly affected by HSUPA users and sector capacity decreases dramatically when one of these users gets connected to a given sector or to one next to it. Also it has been concluded that the capacity decrement is highly sensitive to the location of the HSUPA users. Thus, no more than one HSUPA with a process gain of 16 can be connected to a given base station. In this case, the HSUPA user should interrupt its transmission when it is near to the sector border. No more than one HSUPA user with a process gain of 8 is permitted in a given sector and the sector next to it. When the HSUPA user is at the sector border, its transmission should be disabled