Qualcomm is fighting tough battles on multiple fronts these days – with antitrust regulators, with a hostile bid from Broadcom, with NXP shareholders who are resisting its own bid for NXP, and of course with competitors, old and new, in its core mobile system-on-chip market. With all those challenges, the company still managed to produce some upbeat outlooks for 2018 – but must have thought that the last thing it needed was a credible new challenge in its most successful market, the smartphone modem. That is what it now faces, however. Samsung Electronics has been improving its modem and SoC offerings with its Exynos family, and while this has a small share of the space compared to the dominant Qualcomm,…