• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1534-1539
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• 2001

In this paper, effects of soft handoff region on the reverse link capacity of a DS-CDMA cellular system are investigated. The reverse link capacity of a CDMA cellular system is calculated at a given soft handoff region ratio (SHRR) and path loss model. The results show that the reverse link capacity increases by 1 ∼ 4 channels according to the soft handoff region ratio and the path loss model. However, in the case of the path loss model having a large attenuation exponent ($\mu$ = 5) and a small shadowing standard deviation ( $\sigma$ = 6 dB), the reverse link capacity is no more increased by increasing SHRR.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.481-488
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• 2000

The demands for mobile communication service are growing rapidly. In heavily populated areas, cell split is unavoidable to increase the capacity of the cellular system. Cell splitting makes a cellular system to have mixed cell sizes. For cell planning, it is necessary to analyze the reverse link capacity of a CDMA cellular system with mixed cell sizes. In this paper, we propose a method to calculate the reverse link capacity of a CDMA cellular system with mixed cell sizes. When a macro cell is split into three micro cells, as an example, we calculate the reverse link capacities for the three micro cells and the neighboring macro cells. The results show that as the radius of a micro cell decreases, the reverse link capacity of the micro cell increases, while those of the neighboring macro cells decrease.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.571-579
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• 1997

There are some transmission types on the reverse link of wideband DS-CDMA cellular system. The configurations of logical channels on the reverse link may be different dependent upon the transmission methods of reverse pilot or control signaling. In this paper, we present three transmission types on the wideband DS-CDMA reverse link; no-pilot system, pilot-channel aided system and pilot-symbol aided system. And we compare the performance of three systems in terms of capacity and cell coverage. The pilot-symbol aided system is shown to have the better performance than the pilot-channel aided system in both capacity and cell coverage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1501-1509
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• 1996

Mobile stations can be classified by the transmission power level in CDMA system. Different performance parameters will be given to each class of mobile stations so that the appropriate quality ofservices can be provided. In this paper, it is assumed that there are two clsses of mobile stations. with the classification of mobile stations, analytical models are presented for the estimates of the reverse link capacity and the blocking probability. From the model for the reverse link capacity, the maximum number of each class of mobile stations to be served is derived. It is shown that $E_{b/}$I reduction of 1 dB allows the capacity to be increased by 25% and the data transmission rate and the power control accuracy have a significant effect on the reverse link capacity and the blocking probability. Simulation results are provided for validating the anlaytical estimates of the blocking probability.ocking probability.y.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.440-450
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• 2003

The reverse link of a spectrally overlaid macrocell/microcell cellular CDMA system supporting multimedia traffic is characterized in terms of the required signal power, interference, and capacity. Several narrowband subsystems are overlaid with a wideband subsystem in macrocells, while a single wideband subsystem is operated in a microcell with the same spectrum as the macrocell wideband subsystem. Using a typical propagation model the reverse link signal power and interference are characterized as the relative user signal power and the cross-tier interference factors between the macrocell and the microcell. The reverse link capacity of the overlay system is then analyzed. Analytical results show that the dominant parameters affecting the system performance are the spectral overlay ratio and the distance between the microcell and macrocell base stations. In particular, when the distance equals a half of macrocell radius, optimum performance can be achieved by minimizing the cross-tier interference factors. These results can be applied to CDMA multimedia network planning in heavily populated traffic areas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.562-570
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• 1997

In Direct Sequence Code Division Multiple Access(DS/CDMA) communication systems, it is important to contraol the power of reverse link channel evenly for overall channel capacity. To control the reverse link powers efficiently, it is necessary to estimate signal quality of each reverse link channel. In this paper, we discuss a method to estimate the signal-to-noise ratio(SNR) for each channel by measuring the powers of pilot and noises. Computer simulations are done to show the effectiveness of the scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12B
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• pp.1686-1694
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• 2001

In this paper, we analyze capacities of spectrum sharing scheme for both reverse link and forward link in hierachical CDMA cellular systems with Hot-spot microcell. Capacity analysis is performed through Monte-Carlo simulation by considering microcell radius, location of microcell. and transmission power ratio of microoell to macrocell. From simulation results, we analyzed these effects and derived a general design approach. In addition, the performance of spectrum sharing scheme for each link is analyzed in the capacity plane.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.126-129
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• 1999

In this paper, it is assumed that a mobile radio channel is a Rayleigh distributed multipath fading channel and Erlang capacity and equivalent channel numbers are calculated for the reverse link of a imperfect power controlled DS/CDMA cellular system considering both shadowing and multipath fading. The DS/CDMA blocking probability is calculated based on a new analysis method that considers Erlang capacity and ICF(interference correction factor) using the median value of $E_{b(i)}$/ $I_{o}$ corresponding to each reverse link user. It is showed that the effect of multipath fading must not be ignored in Erlang capacity of the IS-95 DS/CDMA cellular system and the Erlang capacity is decreased according to the increase of the deviation of the imperfect power control, to the decrease of the processing gain, to the increase of the voice activity.y.

• 한국정보통신설비학회:학술대회논문집
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• 2003.08a
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• pp.143-148
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• 2003

In this paper, we focused on the performance of reverse link in 1.8GHz CDMA 1x system including the Tower-Mount LNA in an urban environment. In order to study the benefit of TMLNA, Hata model is used and the effects of multiple cells are considered. Cell coverage extension ratio is proportional to the increased gain of TMLNA in CDMA cell site. However the cell coverage is not extended even if the noise figure of TMLNA is reduced in an urban area. When typical RSSI is between -70dBm and -80dBm, the increased gain and the reduced NF of TMLNA are not impact to the pole capacity of cell site. Namely, the benefit of TMLNA in an urban area is not the problem of capacity but the proble of sensitivity. The results are also shown that reverse link $E_b/N_o$ is improved by minimum 5dB and BER is lower than $10^{-6}$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.12A
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• pp.1828-1835
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• 2000

In this paper, we analyzed the other-cell interference characteristics for various non-uniform traffic distributions and their effects on the capacity of multi-cell CDMA system. We consider three different traffic distributions, i.e., linear, exponential and Gaussian traffic distribution with distribution parameters. Changing the distribution parameter, we can obtain the center-focused distributions or uniform distributions for each model. From the results of other-cell interference calculation we can see that the other-cell interference decreases, as the user concentrates on the base station. Also using frequency reuse efficiency indicating the capacity reduction of a multi-cell system when compared to a single cell system, we evaluate the effect of traffic distribution on the reverse link CDMA capacity. For linear case, the capacity of multi-cell system is reduced to 0.637∼0.867 times that of single cell system. On the other hand, for both exponential and Gaussian cases, the capacity under a multi-cell environment is equal to 70∼100% of that under a single cell. Therefore, we conclude that the average capacity of multi-cell CDMA system are increased when users are likely to be at near the cell base station due to reduced total other-cell interference and decreased when users exist at near the cell edge regardless of traffic distribution models.