| Title | Decision Direct and Linear Prediciton based Fast Fading Compensation for TFI-OFDM |
| Author | *Masanori Yofune, Chang-Jun Ahn, Takeshi Kamio, Hisato Fujisaka, Kazuhisa Haeiwa (Hiroshima City University, Japan) |
| Page | pp. 81 - 84 |
| Keyword | OFDM, CSI, TFI |
| Abstract | Recently, time-frequency interferometry (TFI)-OFDM has been proposed as a channel identification scheme. In TFI-OFDM, under the fast fading channel, the change of channel conditions is too fast to be followed by channel estimator in the receiver. Therefore, too many errors occur in data demodulation processing particularly in the last part of data symbols. To overcome this problem, in this paper, we propose the decision direct and linear prediction based fast fading compensation method for TFI-OFDM. |
| Title | Analysis of CDMA/TDD in Multimode Scenario with Dual-band Operation |
| Author | *Hyeong-Joo Oh, Seung-Hoon Hwang, Jeho Shin (Dongguk University, Republic of Korea) |
| Page | pp. 85 - 88 |
| Keyword | Multimode Scenario, Dual-band Operation, CDMA/TDD |
| Abstract | In this paper, we investigate the capacity of CDMA/TDD in the inner zone of multimode scenario with dual-band operation where high frequency band is used for TDD in the inner zone and lower frequency band is utilized for FDD in the outer zone. The effects of various system parameters such as cell radius, date rate, and time slot allocation are analyzed. |
| Title | New Cross Layer Topology Control Scheme for IEEE 802.16e-based Multi-radio Multi-channel Hybrid Ad Hoc Networks |
| Author | *Yingji Zhong, Kyung Sup Kwak (UWB Wireless Communication Research Center, Inha University, Republic of Korea) |
| Page | pp. 89 - 92 |
| Keyword | Cross Layer, Multi-radio, Multi-channel, Hybrid Ad Hoc Networks, IEEE 802.16e |
| Abstract | A special scenario of the topology in the multi-radio multi-channel hybrid Ad Hoc networks is studied and a new cross layer topology control scheme based on IEEE 802.16e is proposed in this paper. The proposed scheme integrated the attributes both of the new performance evaluation machine check time metric and the topology space in the special scenario. Due to the minimum link occupation, the traffic requirements, the maximal amount of the permitted hops, the aggregated throughput and the scheme overhead are all optimized with the different metrics. |
| Title | Virtual-Cell Frequency Reuse Scheme to Support Seamless Service in Femtocell Environments |
| Author | *Hye Kyung Lee, Min Young Chung (Sungkyunkwan University, Republic of Korea) |
| Page | pp. 93 - 96 |
| Keyword | OFDMA, Frequency reuse, Handoff, Femtocell |
| Abstract | Multiple access technologies based on Orthogonal Frequency Division Multiplexing (OFDM) yield evolutionary advantages for the next generation wireless communication systems. Wireless communication systems based on Orthogonal Frequency Division Multiple Access (OFDMA) increase channel capacity over broad bandwidth and improve the bandwidth efficiency. To maximally use resource in OFDMA-based wireless networks, frequency reuse factor should be one. However, this leads the degradation of performance caused by co-channel interference (CCI). Due to this, we propose an Virtual-Cell Frequency Reuse (VCFR) Scheme to eliminate CCI in cell edge as well as to increase spectral efficiency. Since VCFR allocates the same subset of channel bandwidth in three adjacent sectorized outer regions within three different cells, it is suitable for femtocell environment. Simulation result validates that proposed scheme improves the maximum throughput compared with existing frequency reuse schemes. |
| Title | A Novel Periodogram-Based Frequency Offset Estimation Method for OFDM Systems |
| Author | *Sanghun Kim, Dahae Chong (School of Information and Communication Engineering, Sungkyunkwan University, Republic of Korea), Sun Yong Kim (Department of Electronics Engineering, Konkuk University, Republic of Korea), Seokho Yoon (School of Information and Communication Engineering, Sungkyunkwan University, Republic of Korea) |
| Page | pp. 97 - 100 |
| Keyword | OFDM, frequency offset, periodogram, estimation |
| Abstract | The frequency offset estimation is one of the most important tasks in orthogonal frequency division multiplexing (OFDM) communication systems. To estimate frequency offset, a periodogram-based estimator has been proposed by Ren. The method consists of three estimation steps and gives an accurate results. However, in the second and third estimation steps, the maximum frequency offset that can be estimated is limited by subcarrier spacing. This range is insufficient compared with the overall signal bandwidth, and causes high complexity in the first estimation step. In this paper, we propose a novel frequency offset estimation method with wide estimation range. The proposed method can efficiently extend the estimation ranges without loss of accuracy. |