A Low Complexity Space-Time Block Codes Detection for Cell-Free Massive MIMO Systems

The new generation of telecommunication systems must provide acceptable data rates and spectral efficiency for new applications. Recently massive MIMO has been introduced as a key technique for the new generation of telecommunication systems. Cell-free massive MIMO system is not segmented into cells. Each BS antennas are distributed throughout the environment and each user is served by all BSs, simultaneously. In this paper, the performance of the multiuser cell-free massive MIMO-system exploying space-time block codes in the uplink, and with linear decoders is studied. An Inverse matrix approximation using Neumann series is proposed to reduce the computational and hardware complexity of the decoding in the receiver. For this purpose, each user has two antennas, and also for improving the diversity gain performance, space-time block codes are used in the uplink. Then, Neumann series is used to approximate the inverse matrix in ZF and MMSE decoders, and its performance is evaluated in terms of BER and spectral efficiency. In addition, we derive lower bound for throughput of ZF decoder. The simulation results show that performance of the system , in terms of BER and spectral efficiency, is better than the single-antenna users at the same system. Also, the BER performance in a given system with the proposed method will be close to the exact method.Comment: 5 pages, 4 figures, Accepted for ICEE202

Imaging of trigeminal neuralgia

Trigeminal neuralgia is one of the most frequent neuropathy of the cranial nerves, whose prevalence has been reported between 0.03% and 0.3% in the general population. This condition is a communal manifestation of several possible etiologies. The classical type of trigeminal neuralgia is defined as sudden, usually unilateral, severe, brief, stabbing recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve, with no cause other than a neurovascular compression. Secondary trigeminal neuralgia is the term used to group a large amount of different diseases, which are alike in developing the symptoms of trigeminal neuralgia, due to an insult to the V CN which triggers the complex pathogenesis of pain. These conditions include inflammatory diseases, infections, neoplasms, autoimmune diseases, vascular diseases other than neurovascular conflict, and treatment-related disorders. Generally, the possible mechanisms which lead to the development of neuralgia include nerve distortion/compression by an external mass or damage to the nerve fibers due to an acute or chronic insult. The radiological investigation plays a pivotal role in the diagnosis of trigeminal neuralgia, and MRI constitutes the gold imaging standard in most cases. The trigeminal nerve is a mixed sensory-motor nerve which can be divided anatomically into five segments: brainstem segment, cisternal segment, Meckel’s cave segment, cavernous sinus segment, and extracranial segment. In this paragraph, an anatomy-based imaging approach is proposed to investigate the many causes of trigeminal neuralgia, highlighting the importance of choosing the appropriate sequences and parameters, in the light of a target-suited protocol