- Why LTE sucks (your battery, that is) - Gigaom
- Comparing LTE and 3G Energy Consumption
- Envelope Tracking for improving PA efficiency of mobile devices
For more information see: LTE for UMTS: OFDMA and SC-FDMA Based Radio Access
Specifying which interval the CQI relates to allows the NodeB to track changes in the channel quality between the CQI reports by using the power control commands for the associated downlink (F-) DPCH. The rate of the channel-quality reporting is configurable in the range of one report per 2–160 ms. The CQI reporting can also be switched off completely.
In addition to the instantaneous channel quality, the scheduler implementation in the NodeB should typically also take buffer status and priority levels into account before finalising the data rate for the UE. Obviously UEs for which there is no data awaiting transmission should not be scheduled. There could also be data that is important to transmit within a certain maximum delay, regardless of the channel conditions. One important example hereof is RRC signalling, for example, related to cell change in order to support mobility, which should be delivered to the UE as soon as possible. Another example, although not as time critical as RRC signalling, is streaming services, which has an upper limit on the acceptable delay of a packet to ensure a constant average data rate. To support priority handling in the scheduling decision, a set of priority queues is defined into which the data is inserted according to the priority of the data. The scheduler selects data from these priority queues for transmission based on the channel conditions, the priority of the queue, and any other relevant information.