| Title | Mitigate the Impact of CFO Phenomena for an MC-CDMA System over the Short-term Fading by Applying Multi-dimension Combining Receiver |
| Author | *Joy Iong-Zong Chen, You-Fu Chung (Department of Communication Engineering, Da-Yeh University, Taiwan) |
| Page | pp. 485 - 488 |
| Keyword | MC-CDMA system , MIP, multi-dimension combining (M-D combining), antenna diversity |
| Abstract | Based on the scenario assumed that the CFO (carrier frequency offset), which is caused by the ICI (inter-carrier interference), exists in the environments of short-term fading, a multi-dimension combining (M-D combining) receiver for an MC-CDMA (multi-carrier coded-division multiple-access) system is designed and proposed considerably to overcome the system performance degradation. It is worthwhile claiming that is not only the fading parameter of the correlated-fading model dominates the system performance of an MC-CDMA system, but the number of antenna with the M-D combining receiver also definitely affects the system performance. |
| Title | Evaluation of Flight Size Auto Tuning On 3.5G Commercial Wireless Packet Access Network |
| Author | *Katsumi Sekiguchi, Satoru Imai, Yukie Yamamoto (NTT DoCoMo, Inc., Japan), Noriyoshi Meuchi (DoCoMo Technology, Inc., Japan), Osamu Takahashi (Future University-Hakodate, Japan) |
| Page | pp. 489 - 492 |
| Keyword | Mobile Communications, HSDPA, W-TCP, Evaluation |
| Abstract | We evaluate a performance of Flight Size Auto Tuning (FS-AT) on the commercial network of 3G and 3.5G mobile communication systems. HSDPA expands a bandwidth of IMT-2000 to maximum at 14Mbps. The expanded bandwidth increases BDP on an end-to-end channel. TCP is necessary to set cwnd larger than BDP to achieve maximum throughput. However, if cwnd becomes too large for BDP, TCP sender transmits packets excessively and packets are accumulated on a radio interwoking node. To solve this problem, FS-AT is proposed as a congestion control method for high speed wireless access networks. In this paper, we implemented and evaluated FS-AT on 3G and 3.5G commercial packet access networks. |
| Title | Effect of the Slot Distributed Scheme on the Push-type Packet Compensation Protocol |
| Author | *Koichiro Hashiura (Ibaraki University, Japan), Hiromasa Habuchi (Ibaraki University, Japan) |
| Page | pp. 493 - 496 |
| Keyword | ITS, local broadcasting system, push-type, compensation protocol, IVC |
| Abstract | The push-type packet compensation protocol is that each user autonomously broadcasts the received data to neighbor users for compensating a loss packet. When the user density increases, the average packet acquisition time is deteriorated by the packet collision and shadowing. The slot distributed scheme reduces the packet collision because the user chooses a transmission slot in the frame which consist of Ns slots similar to TDMA. In this paper, the average packet acquisition time of the slot distributed push-type packet compensation protocol is analyzed. Consequently, the slot distributed scheme is effective against increasing of the packet collision. |
| Title | Reduced Complexity Detection for V-BLAST Systems from Iteration Canceling |
| Author | *Taekyu Kim, Sin-Chong Park (Information and Communications University, Republic of Korea) |
| Page | pp. 497 - 500 |
| Keyword | BLAST, MIMO, Successive interference cancellation |
| Abstract | V—BLAST is an effective detection method for MIMO communication system, but has large computational complexity due to its successive iteration. In this paper, we proposed modified V-BLAST to lessen its computational complexity reducing the number of successive iteration. As a result of this simplification, the computational complexity of the detection is lowered significantly. Simulation results show that the proposed V-BLAST reduces calculation complexity by about the 30% while achieving a very close BER performance as the original one. |
| Title | Parallel Sphere Decoder Architecture for MIMO System |
| Author | *Jin Lee, Sin-Chong Park (Information and Communications University, Republic of Korea) |
| Page | pp. 501 - 504 |
| Keyword | MIMO, Sphere decoder, Parallel architecture |
| Abstract | Since Schnorr - Euchner Sphere Decoding (SE-SD) does not guarantee a fixed throughput, the searching cycles of SE-SD should be limited for the practical implementation. Given SE-SD with runtime constraint causes degradation in performance due to the variance of searching cycles, an enhanced SE-SD architecture with a small variance of searching cycles is proposed in this paper for a multi-input multi-output(MIMO) system. Small variance in number of searching cycle is achieved by applying parallel partial Euclidean distance (PED) calculation units to the one-node-per-cycle architecture. Since the proposed architecture is able to evaluate more children nodes in a single cycle, average processing cycles and error performance are significantly improved with a per-block run-time constraint. Our proposed parallel architecture increases the complexity about two times, but it can obtain a 2 dB gain in a 4x4 16QAM system when the runtime constraint is 7 cycles. |