 harmful at the cell border, where the UT might have the same distance to any BS1 and BS2 nearby. It is the purpose of an interference mitigation (IM) functionality in the RRM unit to coordinate neighbor BSs. For the best performance, the IM unit must know the position of neighbor BSs and RNs, as well as its own RNs. It can then decide to share resources in parallel, if the distance between interferers is high enough and the transmit power is reduced according to the proximity of the UT, or to assign a resource exclusively to a UT at the cell border, for example. 8.4.13 Full- and Half-Duplex FDD It is complex to coordinate a radio system with both full- and half-duplex FDD terminals. It looks even trickier to have this working with relays. But it is just a matter of frame organization. Figure 8.10 shows a way to support half-duplex UTs. More details about half-duplex and full-duplex coexistence--especially the timing problem of resource request and grant phases, the scheduling of resources for sev- eral frames in advance, and the avoidance of wasted resources if only a half-duplex © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology is present-are available. The work of Otyakmaz, Schoenen, and Walke [36] is recommended for more information. 8.5 Performance Evaluation The benefit of multihop deployment is now studied in a number of scenarios [13]. The common part is the use of the following parameters, which allow calculation of the throughput from link level to MAC layer: transmit power: 40 Wpeak at the BS (37 dBm), 34 dBm at the RN; bandwidth: b = 18 MHz net (20 MHz system); center frequency: 2.5 GHz; path loss I: non-line-of-sight propagation; path loss II: slow and fast fading effects; interference: neighbor cell BSs interfere (100% load, cluster order 7); noise: accounted for but not serious in interference-limited systems; SINR: the first performance measure below PHY layer; MI: mutual information determined from SINR and modulation; BER: bit error ratio, the PHY 