In this work, Generalized Space-Time Super-Modulation (GSTSM) is introduced which enables the transmission of an additional flexible-rate and highly-reliable information stream concurrently with the conventionally transmitted symbols, without the need for increasing the corresponding packet length. This is attained by jointly exploiting the spatial and temporal dimensions of multiple-antenna systems, which enables efficient detection for conventional and additional information subchannels even in highly correlated channel conditions or AWGN channels. In the context of machine-type communications, GSTSM enables grant-free medium access without transmitting additional headers to convey each machine's signature information. Hence, it is shown that even at an extreme case where the data packets of two users are always colliding, GSTSM offers throughput gains of up to 33% compared to the best examined header-based scheme. For the same scenario, it is shown that GSTSM based on joint multi-user detection provides throughput gains of up to 2.5× compared with the case where users' signals are detected independently. In addition, it yields over 90% improvement in achievable rates compared with the schemes that require centralized medium-access coordination. For both joint and independent signal detection schemes, it is also shown that adopting an iterative detection/decoding approach allows to further improve the throughput gains.

In this paper, we present the recent research findings of our experimental investigation into virtualized Radio Access Networks (vRAN) based on non-ideal fronthaul transport. The experiments are conducted in a Telecom Infra Project (TIP) community lab hosted in BT Labs at Adastral Park; BT’s global research and development headquarters. A wide range of testing and measurements has been executed to characterise the functional behaviour and performance of vRAN based on a low layer functional split with a focus on using G.fast as the fronthaul link. The performance evaluations reveal that the solution operates well in the presence of transport impairments in excess of typical G.fast requirements, thus proving that G.fast can be a suitable transport option for fronthaul. Testing is carried out on two different multi-vendor systems. The more recent of these systems is built in line with the O-RAN fronthaul specification. It is shown that the solution demonstrates promising throughput performance and is robust to a wide range of fronthaul packet loss rates. What is most significant about these experimental results is that it is real evidence of progress of industry efforts to develop an open, best-of-breed, disaggregated, multi-vendor RAN ecosystem that is envisaged for next-generation RAN. In addition, the fact that non-ideal fronthaul can be supported can significantly improve the business case for a number of deployment scenarios.

This work introduces Generalized Space-Time Super- Modulation (GSTSM), a generalization of the recently proposed Space-Time Super-Modulation scheme that enables the transmission of additional, highly-reliable information on the top of conventionally transmitted symbols, without increasing the corresponding packet length. GSTSM jointly exploits the spatial and temporal dimensions of multiple-antenna systems but, in contrast to the initially proposed approach, it does not require the use of space-time block codes. Instead, GSTSM jointly elaborates on the concepts of spatial modulation and spatial diversity, while intentionally introducing temporal correlation to the transmitted symbol sequence. In the context of machine-type communications, GSTSM enables one-shot and grant- free medium access without transmitting additional headers to convey each machines ID. As a result, we show that GSTSM can provide throughput gains of up to 2.5× compared to conventional header-based schemes, even in the case of colliding packets.

We introduce the concept of space-time super-modulation according to which additional low-rate and highly reliable information can be transmitted on top of traditionally modulated and space-time encoded information, without increasing the transmitted block length or degrading their error-rate performance. This is achieved by exploiting the temporal redundancy introduced by the space-time block codes and, specifically, by efficiently mapping transmission patterns to specific information content. We show that space-time super-modulation can be efficiently used in the context of machine-type communications to enable one-shot grant-free joint medium access and rateless data transmission while reducing or even eliminating the need for transmitting preamble sequences. As a result, compared with traditional approaches that use correlatable preamble sequences or encoded preambles to transmit the signature information of transmitted packets, space-time super-modulation can achieve significant throughput gains. For example, we show up to 35% throughput gains from the second best examined preamble-based scheme when transmitting blocks of 200 bits.

We introduce the concept of Space-Time Super- Modulation according to which additional low rate and highly reliable information can be transmitted by further super-modulating blocks of traditionally modulated and space-time encoded information. This is achieved by exploiting the redundant information introduced by the space-time block codes and, specifically, by efficiently mapping transmission patterns to specific information content. It is shown that Space-Time Super-Modulation can be efficiently used in the context of machine-type communications to enable joint medium access and rateless data transmission while minimizing or even eliminating the need for transmitting preamble sequences. Compared with traditional approaches that use encoded preambles or preambles based on Zadoff-Chu sequences to transmit the signature information of transmitted packets, Space-Time Super-Modulation can achieve throughput gains of more than 35% when transmitting blocks of 200 symbols.

Multi-antenna systems play a major role in modern wireless systems due to their outstanding capability in alleviating deconstructive addition of multipath echoes and interferences from other users in wireless media. However, the performance of numerous technologies such as high-performance forward error correction (FEC) codes still have not been sufficiently examined under various multi-antenna wireless propagation environments. This short paper presents the performance of the integrated fully systematic unpunctured (FSU) serial concatenation of quadratic interleaved codes (SCQICs) and Alamouti dual-antenna space-time codes over coherent and incoherent stochastic aeronautical multiple-input single-output (MISO) wireless propagation links.

This paper presents decoupling analysis and numerical performance evaluation of a microwave antenna feeding network for enhancing the isolation between coupled microwave antennas. The RF network linearly combines the input signals in order to force the antennas microwave mutual coupling between the ports become zero. The objective of this RF investigation is to develop a mathematically designed feeding network intended for a suitable use in a 2×2 monopole RF antenna array. The microwave feeding network demonstrates the appropriateness in order to develop a well-established analysis model for microwave feeding networks.