الفهرس | Only 14 pages are availabe for public view |
Abstract The explosive growth in mobile trac demanded more requirements such as; high-speed, high capacity, real-time data, and high-reliability. It is widely accepted that, compared to 4G network, 5G network is expected to achieve 1000 times higher in system capacity, 10 times the spectral eciency, energy eciency and 25 times the average cell throughput. As a result, the dierence between capacity requirements and spectrum lack becomes more obvious. For this reason, it is necessary to change the current transport network technology of wireless communications systems. Nowadays, new innovation approach called -centralized radio access network (Cloud-RAN or C-RAN)- architecture is developed to meet the explosive growth in mobile trac in 5G mobile networks, especially in the need of high-speed, high capacity, real-time data, and high-reliability. In C-RAN ar- chitecture, fronthaul networks provide connectivities between Remote Radio Heads (RRHs) and Base Band Processing Unit (BBU). An important require- ment in 5G fronthaul networks is to be able to forward massive trac to/from a large number of devices connected to RRHs into the BBU pool. Actually, the ber optics technology succeeded in matching all expectations for increas- ing capacity and trac, as it can provide links with the high-speed data rate, low-latency, reliability, and high security. However, optical ber is not de- ployed in several regions, or there is insucient ber optics infrastructure. Therefore, it is necessary to use other wireless communications technologies such as: Free Space Optics (FSO) and Millimeter Wave (mmW) that are suit- able to replace ber optics. In this thesis, the problem of enhancing 5G fronthaul network performance, while sustaining the cost of the network in terms of number of FSO and mmW transceivers is addressed. In the rst part of this thesis, we aim at enhancing the performance of redirected cooperative hybrid FSO/mmW 5G fronthaul networks in C-RAN architecture and compare the results with recent exist- ing topologies. Towards that, two proposed resource allocation schemes are presented as suggested approaches to improve the performance of redirected cooperative hybrid FSO/mmW 5G fronthaul networks. Several objectives such as: network reliability, average transmitted power, and average bit er- ror rate (BER) are considered in our analysis. The schemes are formulated as multi-objective optimization problems (MOOP) and solved by exhaustive search method (ES). The results reveal that the proposed schemes enhance the network performance more than traditional networks, especially at severe weather conditions. In the second part of this thesis, optimal FSO and mmW transceivers place- ment schemes are proposed in order to obtain the strategic locations of FSO and mmW transceivers on RRHs. Towards that, two joint transceiver place- ment and resource allocation schemes are proposed as suggested approaches to improve the performance of redirected cooperative hybrid FSO/mmW 5G fronthaul networks. Several objectives such as: network reliability, average transmitted power, average bit error rate (BER) and number of distrupted links are considered in our analysis. The schemes are formulated as multi- objective optimization problems (MOOP) and solved by exhaustive search method (ES). The results reveal that the proposed schemes help in further enhancement for the resource allocation schemes proposed in the rst part and determine the required number of transceivers at each RRH for the desired performance. |