hannels normalized. system performance of the RF and the base band was prechecked in a two-cable link supporting modulation schemes from BPSK to 64 QAM with an uncoded BER below 10-5. A first prediction about the statistical properties in the transmission scenario can be derived from the singular value (SV) distribution depicted in Figure 11.11. Note that all channels were normalized to allow comparison with simulations. Here, the long tail of SV2 to very small values indicates that spatial multiplexing will sometimes not be supported due to the resulting variation in the achievable SINR at the demodulator. This is a direct consequence of the lack of spatial diver- sity with the 2 X 2 symmetric antenna configurations. Exploiting link adaptation including adaptive MIMO mode and MCS selection should enable us to benefit significantly from the rich scattering multipath environment found in the office scenario. Very similar results were reported with 100-MHz bandwidth at 5-GHz carrier frequency [3] and omnidirectional antennas at both sides of the link. 11.2.4.2 SINR Distribution A practical parameter to choose the optimum MCS level and the MIMO mode is the effective SINR seen at the QAM demodulator. In order to separate the path loss variances from the spatial structure of the channel, all measured channels are nor- malized before calculation of the effective SINR. Channel estimation is performed using broadcasted pilots at the receiver. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology Single Stream Over Full Bandwidth Single Stream on Allocated Resource Blocks Txworst Worst single stream Selected single stream Txbest SINR (dB) SINR (dB) Figure 11.12 Left: SINR distribution for single-stream mode over the full band- width. Right: SINR distribution only for the allocated resource blocks. Single-stream mode. A fixed transmission mode on all resource blocks would result in an effective SINR distribution as experienced in IEEE 802.1 11n transmission techniques. An example