IST-4-027756 WINNER II D6.13.12 v1.0 Final CG “local area ...

WINNER II D6.13.12 v1.0Total number of subcarriers (SCs) 2048Number of SCs used for datatransmission1664Chunk size 15 (time)× 8 (frequency) = 120Number of chunks/framePacket sizeModulation schemeSINR target2 (time) × 208 (frequency)12208 bitsQPSK, rate ½ convolutional code5 dBY−coordinate [m]50454035302520151050Distribution of MSs in WINNER indoor scenarioTransmitterReceiver0 20 40 60 80 100X−coordinate [m]Figure 10.2: Indoor scenario with randomly distributed UTs. Each transmitter selects its receiverrandomly from the distribution.The deployment scenario and the distribution of UTs are illustrated in Figure 10.2. For forming the links,two mobiles A and B are randomly selected from the mobiles distributed in the system, forming a peer-topeer(P2P) link.At the beginning of a snapshot, each transmitter has a buffer which queues a fixed number of packets ofconstant length. The offered load to the system is changed by modifying the packet arrival rate which isassumed to be the same for all UTs. The packets in the buffer are characterized by linearly increasingexpiration time, k Δ t , where k is the position of the packet in the queue, corresponding to the equidistantinter-packet arrival by rate 1 / Δt.The performance of BT-OFDMA applied to local area peer-to-peer (P2P) networks is evaluated on thebasis of four metrics: throughput, data rejection rate, delay and packet expiration rate. Throughput is thenumber of bits that are transmitted successfully. A transmission is considered successful if the receivedSINR is greater than or equal to the SINR target. The data rejection rate corresponds to the averagenumber of bits transmitted per unit time but fail to meet the SINR target. Delay is the time elapsedbetween the beginning of the snapshot to the time the packet is completely transmitted. The packets thatexpire before fully transmitted are assumed to have infinite delay, which for simulation purposes is madeequal to the snapshot duration (100 ms). The packets are assumed to expire if the transmission of theentire packet is not completed before the expiration deadline. The optimum value for the interferencethreshold is determined by simulations as I thres = 100dBm.The performance of the above algorithm is compared against the random allocation scheme. The randomallocation scheme schedules transmission on any chunk with probability p if there is data to betransmitted.Page 65 (86)