Various techniques are presented to improve channel estimation in a wireless system, comprising: transmitting an indication of a physical downlink channel configuration, the physical downlink channel transmission including a demodulation reference signal (DMRS); receiving an indication that the wireless device supports bundling DMRS signals across multiple slots; transmitting, a DMRS configuration, the DMRS configuration including a channel estimation bundle window, the channel estimation bundle window indicating that channel estimation may be performed across multiple slots; transmitting a set of DMRS signals in the channel estimation bundle window, wherein a first DMRS signal of the set of DMRS signals is transmitted in a first slot, and wherein a second DMRS signal of the set of DMRS signals is transmitted in a second slot, and wherein the first DMRS signal and the second DMRS signal are configured for use by the wireless device to estimate a radio channel.