In recent years, wireless audio devices have become a staple of our everyday lives. The growing demands for low-latency and multi-speaker wireless audio streaming have led to the adoption of various technologies such as Wi-Fi and a combination of Bluetooth and other proprietary radio links. Since Bluetooth has a fairly limited range and a peer-to-peer topology, it is unsuitable for streaming audio directly to multiple devices. This is where Wi-Fi based systems gained popularity, owing to their high bandwidth and flexible architecture to support audio streaming to multiple devices over larger distances. This however, comes at the cost of high power consumption and non-deterministic packet latency. With the advent of Bluetooth LE Audio, we now have a framework for broadcast audio streaming over the power efficient Bluetooth LE standard. This thesis explores the performance characteristics of Bluetooth LE Audio systems and draws a comparison with the current landscape of Wi-Fi based audio solutions. This performance data is further used to develop a proof-of-concept LE Audio repeater system, which could help solve the range limitation that has plagued Bluetooth devices in the past. For the specific system developed, a power consumption of around 14 mA was obtained, which is a fraction of the power required by equivalent Wi-Fi based systems. We also obtained a deterministic and relatively low latency of 34 ms and were able to demonstrate the feasibility of implementing repeater nodes using Bluetooth LE Audio. / Under de senaste åren har trådlösa ljudenheter blivit en stapelvara i vår vardag. De växande kraven på trådlöst strömmande ljud med låg tidsfördröjning och flera högtalare har resulterat i olika tekniker såsom WiFi och en kombination av Bluetooth och tillverkarspecifika radiolösningar. Eftersom Bluetooth har begränsningar både i räckvidd och topologi, är den olämplig för direktströmmande ljud till flera enheter. Därför har WiFi-baserade system blivit populära, med sin högre bandbredd och flexibla arkitektur som stöder strömmande ljud till flera enheter över större avstånd. Detta kommer dock på bekostnad av hög strömförbrukning och icke-deterministisk tidsfördröjning. Med tillkomsten av Bluetooth LE Audio, har vi nu ett ramverk för att strömma ljud över den strömsnåla Bluetooth LE-standarden. Denna avhandling utforskar prestandaegenskaper hos Bluetooth LE Audio-system och gör en jämförelse med nuvarande typer av WiFi-baserade ljudlösningar. Resultatet används vidare för att utveckla en prototyp till repeater-system för LE Audio, som kan hjälpa till att öka räckvidden som har hittills har varit en begränsande faktor hos Bluetooth-enheter. För den utvecklade prototypen erhölls en strömförbrukning på ca 14 mA, vilket är en bråkdel av den effekt som krävs av motsvarande WiFi-baserade system. Vi fick också en deterministisk och relativt låg fördröjning på 34 ms och kunde därmed visa att det är genomförbart att implementera repeater-noder för Bluetooth LE Audio.

Bluetooth Low Energy (BLE) is a widely used low-energy version of Bluetooth’swireless protocol. To meet increasing requirements of modern wireless audio devices,Bluetooth LE Audio was released with its new Low Complexity CommunicationsCodec (LC3) being much more data efficient than its predecessor Low Complexity SubBand Coding. Because of its increased data efficiency, LC3 opens the door of exploring usage ofvarious physical layer configurations, especially those with lower data rates. Thedifference in performance when streaming audio with the uncoded LE 2M and 1Mconfigurations, compared to using the LE coded S=2 and S=8 configurations (whichhave a lower throughput) points to a research gap which this thesis aims to fill. To be able to gather data necessary to fill the identified gap, multiple iterations of bothsoftware and hardware artefacts were made. The produced artefacts were designed torun the same Bluetooth version (LE Audio) and switch between the physical layerconfigurations. Throughput and current consumption in varied ranges was measuredthrough usage of the artefacts. The results from the experiments show that for energy optimization, an adaptive schemewould not be beneficial over only using LE 2M. However, an adaptive scheme for thephysical layer can be used for LE Audio to improve range and stability. This doeshowever, come with the cost of increased energy consumption.