The number of applications that is based on location-based services is increasing year by year. This requires that the position of the wireless device can be determined with high accuracy. In cases where GPS does not work alternative techniques for positioning must be developed. To avoid the need for a large number of anchors (devices at a fixed position with known exact position), we will consider a cooperative communication network, where the different user devices exchange information to improve the positioning performance. In this PhD project, we will develop novel physical layer algorithms to estimate a user's position.