No abstract

High throughput, low latency, and high reliability in proximity communications for swarm robotics can be achieved using decentralized cooperative resource allocation schemes. These cooperative schemes minimize the occurrence of half-duplex problems, reduce interference, and allow a significant increase in the achievable swarm density, but requires additional signaling overhead, which makes them potentially more prone to performance degradation under realistic operation conditions. These conditions include both data, signaling, and their interdependence evaluated jointly. The negative impact of the signaling errors requires incorporating enhancement techniques to realize the full potential of the cooperative schemes. Particularly, in this paper and for this purpose, we evaluate the effects of hybrid automatic repeat request (HARQ), link adaptation by aggregation (LAAG) and beam selection by using directional antennas in the cooperative schemes, and compare performance with 3 rd Generation Partnership Project (3GPP) NR sidelink mode 2 (including signaling) using the same techniques. Additionally, we include a comparison of the required number of control signals between sidelink mode 2 inter-UE coordination (IUC) and cooperative schemes, and introduce a decentralized rebel sub-mode behavior in our group scheduling scheme to further improve the performance at the 99.99 percentile. The simultaneous use of all these enhancement techniques in our cooperative schemes considerably reduces the impact of signaling errors and thereby increases the supported swarm size compared to sidelink mode 2.

No abstract

5th Generation (5G) millimeter wave (mmWave) communications are enabled through directive and narrow beams that mitigate these frequencies' challenging propagation conditions. In the future, 5G-Advanced and 6G will go even higher in the frequency spectrum, to allow for progressively larger bandwidths. The need for a larger number of narrower beams will put a strain in the current analog beamforming (BF) based beam management (BM) framework. This paper proposes an alternative signalling method for BM to parallelize the beam sweeping procedure using a hybrid analog-digital (HAD) BF architecture to enable mmWave signal multiplexing with a manageable overhead. The proposed solution is shown to significantly enhance beam alignment performance while reducing signalling overhead and latency.

A critical challenge for 5G is transitioning to the mm-Wave spectrum. Despite providing unprecedented data rates, mm-Waves also suffer high path loss, atmospheric absorption, and higher fluctuating channel conditions, sparking numerous paradigm shifts in the smartphone industry. Extending mm-Wave communications to smartphones requires first a comprehensive study to identify the antenna design/smartphone implementation challenges that impact the quality of communications. This work proposes a two-step assessment metric, the mmWAESI, to evaluate mm-Wave antennas’ potential and limitations regarding their impact on system performance. First, it analyzes the spatial distribution of the smartphone-integrated beam steering array’s radiated power. Then, it evaluates the antenna’s influence on the MIMO performance, using a discrete, time-variant geometrical MIMO channel simulator to recreate any mm-Wave propagation scenario. For enhanced accuracy, mmWAESI accounts simultaneously for several communication aspects: antenna type, realistic radiation patterns, mobile phone form factor constraints, phone orientation, and user influence. The method is illustrated for two different 4-element linear arrays at 39 GHz, based on patch or monopole elements, integrated into smartphones. Their performance is compared under similar conditions, revealing that, unless array switching is employed, the smartphone’s form factor and user influence will mask any potential advantage of the unperturbed array characteristics.