Maintaining concurrency and quality of service across applications is a challenge for traditional Wi-Fi chips that were designed to support single-application use cases: a tablet user in the rear seats who is watching a live stream of an important football game will not tolerate periodic content buffering while the Wi-Fi network is busy mirroring mapping and navigation content from the driver’s smartphone to the head unit.
Traditional Wi-Fi chips use a single Media Access Controller (MAC) to switch across channels and bands, and their performance becomes very limited when multiple applications and multiple bands are required. The solution is to provide two separate Wi-Fi connections simultaneously and in different frequency bands, from the same Wi-Fi access point chip. A radio system-on-chip for automotive systems from Cypress Semiconductor, the CYW89359, offers two separate MACs to enable a feature for concurrent operation called Real Simultaneous Dual Band (RSDB).
The single-chip CYW89359 includes a dual-band, dual-MAC radio, enabling simultaneous operation at both 2.4GHz and 5GHz. Each radio has a separate MAC and physical layer interface (PHY) to its own antenna (see Figure 2). This means that in a typical automotive implementation, a vehicle can run a display-sharing service on the 5GHz radio while providing an uninterrupted internet connection for user devices on the 2.4GHz radio.