lygon area defined in Figure 8.26. The coverage (in percent of the area) of the scenarios differing by the number of relays involved is determined by counting all locations with SINR > SINR™ min For LTE, SINRmin = 0.9 dB holds. Figure 8.30 shows that, in a multihop scenario, increasing amounts of the COV- erage area of the BS are taken over by RNs. The capacity C in bits per second can be used to calculate the spectral efficiency e = Clb using the system bandwidth b. The performance metrics are shown in Table 8.3 for the full area and in Table 8.4 for the densely populated polygon. According to this, two tiers of relays, compared to the BS-only scenario, increase the coverage by a factor of 2.08 overall and 1.53 within the city, as well as the capacity and spectral efficiency by a factor of approxi- mately 1.33 overall and within the city. Figure 8.31 shows the partition of the area served by the BS, H1, or H2 depen- dent on the (circular) radius of the cell. We observe that a first ring of relays comes in early, and a second ring is worth using beginning from 350 m. Again, these numbers show the benefit of using relays. It is not the radio power (which is, of course, more here) but, rather, the expensive fiber access to the BS that is the limita- tion in early rollout phases. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology Figure 8.29 Maximum data rate distribution using all relays in the Jersey scenario. Capacity (Mbit/s) Coverage 25,000 100,000 22,500 90,000 20,000 80,000 17,500 70,000 15,000 60,000 12,500 50,000 10,000 40,000 7,500 30,000 5,000 Square 20,000 Square 2,500 Circle Circle Polygon 10,000 Polygon 0,000 0,000 BS + H01 BS + H01 + H02 BS + H01 BS + H01 + H02 Figure 8.30 The increase of capacity and coverage using relays in the Jersey scenario. C 2009 by Taylor & Francis Group, LLC Multihop Extensions to Cellular Networks Table 8.3 Scalar Results for the Relay Scenario within the Square Area Scenario Coverage (%) Capacity (Mb/s) Spectral Efficiency (b/s