The detection of extensive air-showers with radio method isa relatively young. But promising branch in experimental astrophysics ofultrahigh energies. This method allows one to carry out observations re-gardless of weather conditions and time of day, and the precision of recon-struction of the properties of primary particles is comparable to the clas-sical methods. The main disadvantage of this method is the complexityof the trigger implementation. Radio signals from extensive air-showershave a duration of few tens nanoseconds and amplitudes comparable tothe surrounding background. Moreover, industrial noise, tele- and radiobroadcasting signals, as well as noise from the electronic equipment ofthe experiment, often interfere with measurements. Most of the setupsfor detecting radio emission from extensive air-showers use an externaltrigger from optical or particle detectors. Despite numerous attemptsto develop autonomous (operating with an internal trigger) cosmic rayradio detectors, there is still no established cost-effective technology forthe sparse radio arrays. In the present work, we give an overview of ourprogress in this direction, particularly, we describe a noise generator andsimulation study using data from the Tunka-Rex Virtual Observatory.