In W-CDMA systems, distributions of the interference power and the total transmit power both measured at base stations are respectively used for capacity analysis in the uplink and downlink. For accurate capacity analysis, these quantities must be in proportion to the traffic amount. However, these quantities are no longer in proportion to the traffic amount since the transmit power control maintains the signal to interference power ratio at a constant level. Although the relationship between these measurements and the traffic amount has been investigated, there are still challenges to calculate the statistics such as the blocking probability or the outage probability accurately. This paper proposes a method to calculate the blocking probability by transforming the distributions of these measurements into distributions that are referred to as "traffic equivalent distributions," where the distributions are automatically adjusted according to the traffic amount. The calculated results show good agreement with the results obtained by dynamic computer simulations in the uplink, and show good agreement in the downlink as well when the traffic load is light. Accurate calculation of the blocking probability using a feedback loop and the observation of the traffic equivalents is also reported.

Transmit power planning in the W-CDMA downlink, especially planning of the total transmit power of base stations and their apportionment to common control channels, is discussed taking cell coverage planning into account. A transmit power planning procedure is proposed for common control channels based on both link-level and system-level simulations. An analysis on optimum power allocation for common pilot channels is also presented. Link budgets that are applicable to downlink common control channels are developed and presented.

While higher chip rate can provide better performance for Direct Sequence/Code Division Multiple Access (DS/CDMA) systems due to larger process gain, it may also induce spectrum emission to adjacent channels, i. e. , adjacent channel interference. Especially, if different operators use adjacent channels in the same area with uncoordinated power levels, such interference becomes large, and excessively higher chip rate will decrease the efficiency of a system. In this context, this paper evaluates the relation between chip rate and capacity in DS/CDMA cellular communication systems considering adjacent channel interference from other systems. First, the classification of adjacent channel interference between two independent DS/CDMA systems is described, and the concrete interference levels are calculated for several chip rates. Then, by using computer simulation, the system CDMA capacity is evaluated under adjacent channel interference. From these results, we can find that the excessively higher chip rate can not always provide the larger system CDMA capacity in spite of the larger process gain, and there exists the appropriate chip rate for a certain given bandwidth.

Sea clutter was measured using an X-band radar at very high grazing angles between 8.2 and 17.5. The sea state was 7 with the wave height of 6 to 9m. The wind velocity was 25m/s. It is shown that sea clutter amplitudes obey the log-normal and K distributions using the Akaike Information Criterion (AIC) , which is more rigorous fit to the distribution to the data than the least squares method.

In communication systems such as mobile telecommunication systems and the Internet, resource sharing among coexisting real-time and non-real-time services is extremely important to provide multimedia services. This paper analytically investigates the performance of the packet data control algorithm proposed in. This algorithm efficiently uses radio resources by utilizing the remaining capacity that is not used by real-time services. The state probability vectors and transition probability matrices of both the real-time and non-real-time services are first derived and then the delay characteristics, the outage probability of voice users, and the outage probability of data users are evaluated. A performance analysis with high bit-rate non-real-time services is also presented.

The next generation mobile communications systems must support multimedia communications services as well as conventional voice service. DS-CDMA is regarded as the most promising candidate, because it is indispensable to cope with multimedia. The system capacity of DS-CDMA system is limited by the total interference level. As a result, in DS-CDMA systems many users suffer very poor communication quality if the total interference level exceeds this limit. Therefore, this paper considers smoothing interference fluctuation using the difference between voice and data in a type of QoS (quality of service). In other words, voice communication is suitable for a loss system because the quality of voice communication is delay-sensitive. On the other hand, data communication is suitable for a waiting system because the quality of data communication is non-delay-sensitive. This paper focuses on a system that applies a circuit switching method for voice traffic and a reservation type packet switching method for data traffic and proposes a data traffic control method. In this proposed data traffic control method, a base station controls data transmission from a mobile station to utilize unused voice traffic resources. As a result, the proposed method achieves highly efficient use of the radio spectra by smoothing interference fluctuation in DS-CDMA systems. This paper evaluates the performance level of the proposed method from a system capacity standpoint. It is shown that the proposed method achieves higher system capacity in voice/data integrated transmission.