Patent ID: 8559405
Filing Date: 2013-10-15
Classification: H04J,H04L,H04W

Abstract:
1. A method comprising: a) receiving, by a wireless device, at least one control message from a base station, said at least one control message causing in said wireless device: b) receiving, by said wireless device, a control command configured to cause transmission of a random access preamble on random access resources of said reference secondary cell in said secondary cell group; and c) receiving, by said wireless device, a random access response on a primary cell in said primary cell group, said random access response comprising a timing advance command for said secondary cell group; d) transmitting first uplink signals in said secondary cell group, by said wireless device, employing a synchronization signal on said reference secondary cell as a secondary timing reference, said reference secondary cell being an activated cell in said secondary cell group; e) selecting, autonomously by said wireless device, a new activated secondary cell in said secondary cell group as said secondary timing reference if all of the following conditions are satisfied: f) transmitting second uplink signals in said secondary cell group, by said wireless device, employing a second synchronization signal on said new activated secondary cell as said secondary timing reference.