The disclosure relates in some aspects to techniques for improved channel estimation. For example, a device can specify a pilot structure where pilot density differs over time. As another example, a device can indicate that a pilot from a prior transmission time interval (TTI) can be used for channel estimation. As another example, a device can employ frequency domain physical resource block (PRB) bundling with the bundling information signaling. As yet another example, a device can use an adjustable traffic-to-pilot ratio (TPR) for throughput optimization. Other aspects, embodiments, and features are also discussed and claimed.