worst PhyMode, the highest (transmit) Relay -1000 Relay 3 Relay 2 -2000 -3000 -3000 -2000 -1000 X (m) Figure 8.18 Indication of which element of (BS, RN1, RN2, RN3) serves best (i.e., gives the highest data rate to a UT) over the cell area in a coverage-increas- ing scenario. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology -1000 -2000 -3000 -3000 -2000 -1000 X (m) Figure 8.19 SINR over the cell area. The different colors indicate the signal strength of the best serving element (numbers in decibels). power consumption, and the worst performance. This scenario makes sense for urban areas where the capacity demand per area at the border is the same as near the BS, SO we approximate the "constant rate offer" to match the demand (see Figure 8.1). -1000 -2000 -3000 -3000 -2000 -1000 X (m) Figure 8.20 Maximum data rate achievable over the area in a coverage-increas- ing scenario. Due to the first hop resources, there is a lower maximum level in the relay-supported areas. C 2009 by Taylor & Francis Group, LLC Multihop Extensions to Cellular Networks -1000 -1500 -1500 -1000 X (m) Figure 8.21 SINR in a multihop cell to increase the capacity. Here, only the SINR of the best server is shown. This produces the sharp edges at half of the radius. Beyond that, the relays are chosen as the better server. -1000 -1500 -1500 -1000 X (m) Figure 8.22 Maximum data rate achievable over the area in a capacity-increas- ing scenario. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology -2000 -4000 -6000 -6000 -4000 -2000 X (m) Figure 8.23 Best server chosen in a capacity-increasing scenario. 8.5.3 Parameter Discussion Some parameters can be tuned [24]; their default values include: cluster order: C = 7; spatial reuse: time division multiplexing (TDM) or spatial division multi- plexing (SDM); relay antenna gain: G = 14 dB or G = 0 dB; sectors per cell: S = 1; coverage-optimized (CO) versus throughput-optimized (TO) scenario; and directional antenn