This paper compares by computer simulation the achievable throughput performance employing fast packet scheduling algorithms focusing on the throughput of each user in High Speed Downlink Packet Access (HSDPA). Three packet scheduling algorithms are employed: the Maximum carrier-to-interference power ratio (CIR), Proportional Fairness (PF), and Round Robin (RR) methods. The simulation results elucidate that although the Maximum CIR method achieves an aggregated user throughput within a cell higher than that using the PF and RR methods, the PF method is advantageous because it enhances the user throughput for a large number of users with a lower received signal-to-interference power ratio (SIR), who are located outside the normalized distance of 0.6-0.7 from a cell site (this corresponds to the area probability of 50-60% within the cell) compared to the Maximum CIR method. It is also shown that when the PF method is employed, the probability of user throughput of greater than 2 Mbps in the vicinity of the cell site becomes approximately 45% (5%) for L = 1-path (2-path) fading channel, while it is almost 80% (50%) when using the Maximum CIR method. Finally, we show that the average user throughput in a 2-path Rayleigh fading channel is reduced by approximately 30% compared to that in a 1-path channel due to severe multipath interference (MPI) and that the average user throughput is strongly affected by the total traffic produced within a cell, which is directly dependent on the number of users within a cell and the data size per packet call.

This paper proposes a unified packet scheduling method that considers the delay requirement of each traffic data packet whether real time (RT) or non-real time (NRT), the channel conditions of each accessing user, and the packet type in hybrid automatic repeat request (ARQ), i.e., either initially transmitted packet or retransmitted packet, in the forward link for Orthogonal Frequency and Code Division Multiplexing (OFCDM) wireless access. In the proposed packet scheduling method, the overall priority function is decided based on PTotal = αDelayPDelay + αTypePType + αSINRPSINR (PDelay, PType, and PSINR are the priority functions derived from the delay requirement, type of packet, and the received signal-to-interference plus noise power ratio (SINR), respectively, and αDelay, αType, and αSINR are the corresponding weighting factors). The computer simulation results show that the weighting factor of each priority function as αType/αDelay = 0.6, αSINR/αDelay = 0.4 assuming the linear-type function in PDelay and a constant-type function in PType is optimized. Furthermore, we show that the outage probability for achieving the packet loss rate (PLR) of less than 10-3 for non-real time (NRT) traffic users employing the proposed packet scheduling method is reduced by approximately two orders of magnitude compared to that using the Priority Queuing (PQ) method while maintaining the PLR of real-time (RT) traffic users at the same level as that using the PQ method.

This paper investigates the uplink throughput performance and the interference power to other cells using an Evolved UTRA (E-UTRA) laboratory and field experimental system. In E-UTRA uplink, the near-far problem is not an issue since the orthgonality among the users within the target cell is maintained. Therefore, the fractional transmission power control (TPC), in which the target level of TPC is adjusted according to the path loss level, can be adopted. Thus, it is expected the high cell throughput and the large coverage area by combining fractional TPC, adaptive modulation and channel coding (AMC), and variable resource block (RB) allocation. The indoor and field experimental results show that the peak throughput of approximately 45 Mbps is achieved by allocating a wider bandwidth and setting higher target level for the UE located near the cell site while keeping the adjacent cell interference level almost the constant. We also showed that the system capacity can be improved by 50% in simple cell model by applying the AMC and the fractional TPC.

This paper proposes block-wise resource block (RB)-level distributed OFDMA transmission with ND-block division in order to obtain the frequency diversity effect even for low-rate traffic (here ND indicates the number of virtual RBs within one physical RB) in Evolved UTRA downlink. More specifically, we propose a constraint rule such that distributed transmission is multiplexed into a different physical RB from that of localized transmission in order to achieve the same resource assignment and independent decoding between the distributed and localized transmissions. Based on the proposed rule, a virtual RB for distributed transmission is segmented into ND blocks with the size of 1/ND of the original virtual RB. Then, the ND virtual blocks with the size of 1/ND are mapped together into each ND physical RB in a distributed manner, resulting in a large frequency diversity effect. Numerical calculations show that the block-wise RB-level distributed transmission can reduce the number of control signaling bits required for resource assignment compared to the subcarrier-level distributed transmission scheme, which provides the best performance. Moreover, a system-level simulation shows that the loss in the cell throughput employing the block-wise RB-level distributed transmission compared to that using the subcarrier-level transmission is only within 3-4% when the channel load is 0.5 and 1.0, i.e., the maximum loss is 3-4% at approximately 90% in the cumulative distribution function (CDF).