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This paper investigates the spectral efficiency achieved through uplink joint transmission, where a serving user and the network users (UEs) collaborate by jointly transmitting to the base station (BS). The analysis incorporates the resource requirements for information sharing among UEs as a critical factor in the capacity evaluation. Furthermore, coherent and non-coherent joint transmission schemes are compared under various transmission power scenarios, providing insights into spectral and energy efficiency. A selection algorithm identifying the optimal UEs for joint transmission, achieving maximum capacity, is discussed. The results indicate that uplink joint transmission is one of the promising techniques for enabling 6G, achieving greater spectral efficiency even when accounting for the resource requirements for information sharing.

Approaching 20th anniversary of the tsunami struck Aceh, almost no trace of the tsunami was visible. Nowadays, areas that were hit the hardest by the tsunami have grown into dense residential areas. Many relief houses built by various donors on different locations have been transformed, adapting to the needs of their inhabitants, including the relief houses in Ulee-lheue. Based on Habraken theory of spatial transformation, the purpose of this study is to identify the spatial transformation that occurred in post-tsunami relief houses in Gampong Ulee Lheue, Banda Aceh. This study employs qualitative methodology with a descriptive analysis approach. The primary data is taken through interviews and observations while secondary data is obtained through documentation of previous study. The sample were chosen purposively represent houses built by Uplink, BRR and Baitul Mal. There were nine relief houses chosen that experience transformations. Following Habraken step, the analysis of this study is framed by spatial structure and spatial value by comparing the current transformation and the basic type of relief houses. The results show changes have been found in the form of expansions that are dominated to the back and to the side. Additionally, the Uplink relief houses expand downwards. This transformation also resulted changes in the spatial structure included, hierarchy, house orientation, spatial patterns, circulation and access and increased territorial area. In term of spatial value, the changes can be found in usage space, economic and social dimensions. Contribution of this research is to provide knowledge in transformation and post-disaster housing.

In the CTCS system, the balise plays an important role in supporting the normal operation of trains. Based on this, this article studies the performance of the uplink of the balise transmission system under different speed conditions from three perspectives: theory, simulation, and measurement. Based on an in-depth analysis of the energy and data transmission process between the vehicle antenna and the ground balise, relevant electromagnetic theoretical models such as the input and output characteristics of the balise and the antenna magnetic field distribution are established. An electromagnetic field model of the balise transmission system is established using Maxwell software, and the simulation results are obtained. An experimental environment is built using responder products and the simulation results are analyzed. Methods are explored to improve the adaptability of responder transmission systems under high-speed operating conditions.

In this paper, we present two novel low-complexity transmission schemes for optical ground station (OGS)-satellite free space optical (FSO) uplink. Specifically, the TCAM-scheme which is a joint dual-branch threshold combining and adaptive modulation scheme and the SCAM-scheme which is a joint dual-branch selection combining and adaptive modulation scheme. In both schemes, the data rate is adjusted according to the instantaneous received combined SNRs at the satellite. We analyze the performance of the proposed schemes in terms of the outage probability, the average spectral efficiency and average bit error rate, while considering both subcarrirer intensity modulation/direct detection (SIM/DD) and coherent FSO detection techniques. Numerical results show that both TCAM and SCAM schemes provide better performance as compared to a single FSO uplink, while SCAM scheme enjoys better performance than TCAM scheme. This comes at the expense of increased complexity of the SCAM scheme. Also, coherent FSO detection technique shows better performance than the SIM/DD FSO detection technique for both schemes. The choice of which scheme and which FSO detection technique to use is a compromise of required quality of service and complexity.

In order to reduce the massive computational overload at the central processing unit in the intelligent reflecting surface (IRS)‐aided cell‐free (CF) massive multiple‐input multiple‐output (m‐MIMO) systems, multiple local processing units (LPUs) are introduced in this letter for uplink signal detection. The analytical closed‐form expressions for the bit error rate (BER) and achievable sum spectral efficiency (ASSE) obtained by the zero‐forcing decoder in uplink IRS‐aided CF m‐MIMO systems with LPUs are derived, and the corresponding computational complexity (CC) is further analysed. The simulation results validate their correctness. Compared to the single IRS aided uplink m‐MIMO systems composed of centralized base station with receive correlation, the CF architecture incorporating LPUs demonstrates significantly superior performance in terms of both improved BER and ASSE characteristics with substantially reduced CC.

This paper presents a resource optimization method for the 2-step random access (RA) procedure in the 5 th generation new radio (5G NR). In 2-step RA, the MsgA includes a sequence as a preamble on the physical random access channel (PRACH) and uplink payload on the physical uplink shared channel (PUSCH). The mapping between PRACH slots and PUSCH slots is specified by system configuration parameters. The network reserves the corresponding PUSCH resource fixedly, regardless of the random access occasion (RO) occupancy rate and the uplink data traffic request. It deprives the uplink scheduling resource efficiency in cases of some RO unoccupied. To achieve higher utilization efficiency, this paper studies the reusing of the PUSCH slots and occasions fixed to RACH in MsgA. By detecting the preambles in RO before the corresponding PUSCH slots, the network acquires the occupancy of the RO. Then the PUSCH occasion (PO) in reserved PUSCH can be released, which conforms to the RO detection result. The release of the previously reserved PUSCH occasions can be rescheduled and reused by the user equipment (UE) for uplink data transmission. Hence more wireless resources can be scheduled in contrast to the existing allocation of uplink share channel in 2-step type random access. It suggests that using the method improves the efficiency of resource utilization.

5G will have to cope with a high degree of heterogeneity in terms of services and requirements. Among these latter, the flexible and efficient use of non-contiguous unused spectrum for different network deployment scenarios is considered a key challenge for 5G systems. To maximize spectrum efficiency, the 5G air interface technology will also need to be flexible and capable of mapping various services to the best suitable combinations of frequency and radio resources. In this work, we propose a comparison of several 5G waveform candidates (OFDM, UFMC, FBMC and GFDM) under a common framework. We assess spectral efficiency, power spectral density, peak-to-average power ratio and robustness to asynchronous multi-user uplink transmission. Moreover, we evaluate and compare the complexity of the different waveforms. In addition to the complexity analysis, in this work, we also demonstrate the suitability of FBMC for specific 5G use cases via two experimental implementations. The benefits of these new waveforms for the foreseen 5G use cases are clearly highlighted on representative criteria and experiments.

The proposed resource allocation algorithm with joint power control and user pairing addresses the problem of degraded uplink user fairness due to cross-cell interference in NOMA uplink and improves user fairness. In the power control section, by decoupling power control from user pairing, the WOA algorithm is proposed in the statistical channel state scenario to solve the nonconvex optimization problem of intra-user pair fairness; in the user pairing section, the PTS algorithm is proposed to introduce randomness into the algorithm to improve the algorithm’s global search performance, solve the local optimum problem of integer programming, and improve inter-user pair fairness. Simulation results show that relative to the α -fairness comparison algorithm, the algorithm in this paper can improve fairness by about 5% under different interfering user densities, cell coverage radius, and tiny area transmit power.

Wireless- and 5G-enabled industrial automation is expected to include a plethora of different applications with a wide variety of requirements. In this article, evaluations are undertaken for the deployment of 5G in realistic industrial production environments with realistic deployment settings. Both deployments using commercial 5G systems and a 5G prototype system including pre-commercial and standard compliant URLLC functionality have been investigated. Systematic latency and reliability measurements were performed, over the air and in live networks, for different packet sizes, different devices, and networks with different capabilities (at different sites) to characterize the expected performance. The results indicate that today’s 5G latency performance significantly depends on packet size, transmission direction (uplink or downlink), and network configuration as well as on the end device’s design and capabilities. Our over-the-air measurements also empirically show that 5G technology and future networks have the capability of providing one-way latency of around 1 ms in both uplink and downlink for the various packet sizes tested. It is concluded that the requirements for very low latencies can be achieved with high reliability guarantees, as required in some of the most stringent industrial IoT applications.

This paper investigates multiple access schemes for uplink and downlink transmissions in cellular networks with massive Internet of Things (IoT) devices. Recall that single-carrier frequency division multiple access and orthogonal frequency division multiple access, which are orthogonal multiple access (OMA) schemes, have been conventionally adopted for uplink and downlink transmissions in narrow-band IoT, respectively. Unlike these OMA schemes, we propose two non-orthogonal multiple access (NOMA) schemes for cellular IoT with short-packet transmissions. Especially, a generalized expectation consistent signal recovery-based algorithm is proposed to estimate active devices, channel state information and data in uplink transmission, where all of the active devices are allowed to transmit their pilots and data through the same resource block without authorization. On the other hand, the active devices estimated during uplink transmission are grouped for downlink transmission with a trade-off between performance and detection complexity. Additionally, the data error rates are analysed for both uplink and downlink transmissions with low-resolution analog-to-digital converters (ADCs), where the effects of critical parameters such as the estimation error, ADC bits, packet length, and message bits are revealed. Both simulation and analytical results are provided to demonstrate the excellent performance of the proposed NOMA schemes and algorithms, especially for active device, channel, and data estimations. More importantly, the obtained results show that the data error rate performance of downlink NOMA is superior to that of OMA when the message bits of devices in one group are selected following the proposed strategy.