الفهرس 
Chapter 1 IntroductionOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
This thesis introduces LTE-A downlink physical layer network with multiple relay
stations. RSs improve the weak received signal at User Equipments (UEs). LTE-A with
RSs can be used to increase the coverage area of BSs and increase the system capacity. It
also enhances the service of the user at cell edge and cover shadowed areas. The
performance of the proposed LTE-A network is illustrated and modeled. This thesis studies
the effect of different environments scenarios of the WINNER channel. The received
signals at UEs are mathematically derived and analyzed. The SER and capacity are
calculated for different UEs scenarios to investigate the effect of RSs in LTE-A Network.
Simulation results reveal that UEs which receive multiple signals from RSs have low SER
values for SNRs up to 40 dB and enhances the service performance of the UEs at cell edge.
MIMO AF RSs based OSTBCs for the LTE-A downlink physical layer is proposed
in this thesis. The performance of proposed system is compared with the same system that
does not employ OSTBCs in its RSs. The proposed system performance is illustrated for
UEs that receive signals through different paths. Results show that RSs based OSTBCs
give better performance and achieve higher diversity gains.
This thesis presents the performance of LTE-A downlink physical layer with
different MIMO detection algorithms. A scalable and applicable Ordered Successive
Interference Cancellation- based Sphere Decoding (OSIC–based SD) algorithm with
higher performance is proposed. The proposed algorithm is characterized by dividing a
large MIMO detector into small dimension blocks, and then the general detection method
such as OSIC can be applied in each part with smaller dimension. We investigate the
performance of the proposed algorithm and compare its performance with ZF, MMSE, ML
algorithms. The proposed algorithm is mathematically illustrated and evaluated for
different transmit and receive antennas. Simulation results show that the proposed
algorithm provides a better performance and low BER values compared to classical
algorithms.
This thesis also proposes a scalable and near optimum OSIC-based K-Best
algorithm with higher performance. The proposed OSIC-based K-Best algorithm is
characterized by low complexity by dividing a large MIMO detection problem into small
sub-problems. The proposed algorithm is divided into several basic building blocks with
ABSTRACT iv
small dimension to reduce complexity. This algorithm utilizes the K-Best algorithm for
first data stream with high SINR, and then applies an OSIC-MMSE to detect the other data
streams. This thesis investigates the performance of the proposed algorithm and compares
its performance with the other algorithms. The performance of the proposed algorithm is
mathematically illustrated and evaluated for different antennas cases. Simulation results
show that the proposed algorithm provides a better performance and gives low BER
values.
This thesis also proposes a scalable and implementation efficient OSIC-based ML
algorithm in a quantized space with higher performance for MIMO detection. It is
characterized by dividing the overall OSIC detector into small dimension blocks to reduce
complexity. The proposed algorithm utilizes ML algorithm in a quantized space to detect
the first data streams and overcome error propagation problem. Then, it applies small
dimension OSIC block to detect other data streams. The mathematical analysis is also
given. This thesis shows BER performance of the proposed algorithm and compares its
performance with ZF, MMSE, OSIC-MMSE and ML algorithms. This thesis also presents
the computational complexity to show that it gives lower complexity close to optimal ML
algorithm. Finally, the proposed algorithm enhances the detection in LTE-A system and
gives results close to optimum ML.
This thesis also investigates the performance of Multicarrier Delay Diversity
Modulation (MDDM) system with space time code techniques. MDDM system that based
on Alamouti codes is proposed. The performance of the proposed technique is
mathematically illustrated and modeled. The received signals at MDDM receiver are
mathematically derived and analyzed. Simulation results demonstrate that the proposed
MDDM system enhances the performance of classical MDDM system and gives low
values of BER compared with the classical case.
Deploying Space-Time Trellis Code (STTC) in MDDM system can allow cost
efficient and flexible system compared to classical MDDM system with multiple cyclic
delays. So, MDDM system based on STTC is proposed. The MDDM system is modeled
for two and four transmit antennas. This thesis compares the performance of the proposed
MDDM system with conventional MDDM system in the case QPSK, 8PSK and 16QAM
STTCs. Simulation results demonstrate that the proposed MDDM system enhances the
performance of classical MDDM system.