inimum allocation shown in Figure 2.5. When LTE and LTE Advanced in Releases 8-11 Sub-carrier mapping Cyclic modulator Extension UE Transmitter frequency Total radio BW (e.g. 20 MHz) eNodeB Receiver Cyclic Extension Equalize Removal Demodulator Figure 2.4 LTE uplink principle more bandwidth is allocated, the duration of a single symbol in the uplink direction becomes shorter due to the increased symbol transmission rate. The generation of the uplink slot con- tent shown in Figure 2.6 includes the use of reference signal sequence which is known in the eNodeB receiver as well and is used by the eNodeB receiver to facilitate the channel estimation in the uplink direction. The uplink structure includes pre-determined locations for physical layer control information, such as ACK/NACK feedback for packets received in the UE 2 Allocation UE 1 Allocation 1 ms Sub-frame frequency Allocations from eNodeB on PDCCH Figure 2.5 Example of uplink resource allocation LTE Small Cell Optimization Reference Symbols Resource Elements Control Information Elements modulator symbols Signal Reference Subcarriers Symbols Control Information Elements 0.5 ms slot 1 ms sub-frame = PUSCH Figure 2.6 Generation of uplink slot contents for transmission downlink direction or Channel Quality Information (CQI) for providing feedback to enable the frequency domain scheduling in the downlink direction. The Physical Uplink Control Channel (PUCCH) can be used when there is no uplink allocation available for Physical Uplink Shared Channel (PUSCH). In case UE has earlier run out of data, PUCCH can be used to send scheduling request when more arrives to the buffer if there are no resource allocations existing. Other information to be sent on PUCCH included CQI feedback and ACK/NACK information for the packets received in the downlink direction. The frequency resource for PUCCH is located at band edges, as shown in Figure 2.7. A UE transmitting PUCCH will send first one 0.5 ms slot at one band edge and other slot then with PUCCH allocations PUSCH allocati