In the third quarter, according to network testing firm OpenSignal, AT&T showed a slight increase in latency speeds on its LTE network when compared with the operator's results from the second quarter. Sprint remained the carrier with the lowest LTE latency speeds. Latency is defined as the time it takes for a source to send a packet of data to a receiver. Latency is typically measured in milliseconds. The lower the latency (the fewer the milliseconds), the better the network performance. FierceWireless, in partnership with OpenSignal, is hoping to shed some light onto the latency issue and track latency measurements of the four Tier 1 carriers. Find out how they performed in this special report.