REVERSE LINK CDMA SYSTEM CAPACITY EVALUATION FOR STRATOSPHERIC PLATFORM MOBILE COMMUNICATIONS

We propose an analysis of reverse link CDMA multispot beam stratospheric platforms (SPF) in this paper. The SPF iscurrently proposed as a novel wireless technology for the development of the next generation fixed and mobilecommunications. The geometry of this technology is different from that of the terrestrial but rather similar to thesatellite based cellular system. However, evaluation on the CDMA system capacity of this technology has not beenmuch reported. This paper addresses all possible multiple access interference analyses including the effects of channelfading and shadowing in order to evaluate the system capacity. Single SPF and multiple SPF model are evaluated underperfect power control and imperfect power control. The results indicate that in SPF systems the reverse link CDMAcapacity is significantly reduced because of the power control imperfections. Moreover, in multiple SPF model theinterference caused by the users in overlapped region is not trivial. We found that because of this problem the capacityis reduced for both speech and real-time data applications compared with the single SPF model even though theassumption of perfect power control can be made. In order to improve the system capacity we proposed two methods,first is to increase the minimum elevation angle definition for each platform and the second is to employ an adaptiveantenna.Keywords: stratospheric platform, cellular communication, CDMA, power control, outage probability, adaptiveantenn

Delivering Extended Cellular Coverage and Capacity Using High Altitude Platforms

Interest in delivering cellular communication using a high-altitude platform (HAP) is increasing partly due to its wide coverage capability. In this paper, we formulate analytical expressions for estimating the area of a HAP beam footprint, average per-user capacity per cell, average spectral efficiency (SE) and average area spectral efficiency (ASE), which are relevant for radio network planning, especially within the context of HAP extended contiguous cellular coverage and capacity. To understand the practical implications, we propose an enhanced and validated recursive HAP antenna beam-pointing algorithm, which forms HAP cells over an extended service area while considering beam broadening and the degree of overlap between neighbouring beams. The performance of the extended contiguous cellular structure resulting from the algorithm is compared with other alternative schemes using the carrier-to-noise ratio (CNR) and carrier-to-interference-plus-noise ratio (CINR). Results show that there is a steep reduction in average ASE at the edge of coverage. The achievable coverage is limited by the minimum acceptable average ASE at the edge, among other factors. In addition, the results highlight that efficient beam management can be achieved using the enhanced and validated algorithm, which significantly improves user CNR, CINR, and coverage area compared with other benchmark schemes. A simulated annealing comparison verifies that such an algorithm is close to optimal

成層圏飛翔体通信における無線通信路及びその性能に関する研究

制度:新 ; 文部省報告番号:甲2383号 ; 学位の種類:博士(国際情報通信学) ; 授与年月日:2007/3/15 ; 早大学位記番号:新447

Mobile and Wireless Communications

Mobile and Wireless Communications have been one of the major revolutions of the late twentieth century. We are witnessing a very fast growth in these technologies where mobile and wireless communications have become so ubiquitous in our society and indispensable for our daily lives. The relentless demand for higher data rates with better quality of services to comply with state-of-the art applications has revolutionized the wireless communication field and led to the emergence of new technologies such as Bluetooth, WiFi, Wimax, Ultra wideband, OFDMA. Moreover, the market tendency confirms that this revolution is not ready to stop in the foreseen future. Mobile and wireless communications applications cover diverse areas including entertainment, industrialist, biomedical, medicine, safety and security, and others, which definitely are improving our daily life. Wireless communication network is a multidisciplinary field addressing different aspects raging from theoretical analysis, system architecture design, and hardware and software implementations. While different new applications are requiring higher data rates and better quality of service and prolonging the mobile battery life, new development and advanced research studies and systems and circuits designs are necessary to keep pace with the market requirements. This book covers the most advanced research and development topics in mobile and wireless communication networks. It is divided into two parts with a total of thirty-four stand-alone chapters covering various areas of wireless communications of special topics including: physical layer and network layer, access methods and scheduling, techniques and technologies, antenna and amplifier design, integrated circuit design, applications and systems. These chapters present advanced novel and cutting-edge results and development related to wireless communication offering the readers the opportunity to enrich their knowledge in specific topics as well as to explore the whole field of rapidly emerging mobile and wireless networks. We hope that this book will be useful for students, researchers and practitioners in their research studies