With the ever-growing popularity of smartphones, new services are emerging where the local and positioning aspects becomes more important. Additionally, new types of traffic, such as vehicle-to-vehicle communications are being developed. In order to address these new trends, release-12 of LTE has started to evaluate, and possibly standardize, solutions for device-to-device (D2D) communication. This provides the foundations for the deployment of a D2D overlay. However, this should be viewed as a first step, and future LTE releases should encompass more advanced D2D communication techniques and architectures. In this paper, after reviewing the standardization progress for LTE in release-12, several possible improvements are examined for future releases both D2D discovery and communication. It is shown that the future D2D architecture should exploit the network when possible in order to provide an improved user experience and satisfy the need for more local services.
