scholarly journals Chip-Level HARQ Chase Combining for HSUPA

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Mohamed Et Tolba ◽  
Samir Saoudi ◽  
Raphaël Visoz ◽  
Tarik Ait-Idir
Keyword(s):  
High Speed ◽  
Space Time ◽  
High Order ◽  
Diversity Gain ◽  
Automatic Repeat Request ◽  
Time Diversity ◽  
Combining Efficiency ◽  
Time Linear ◽  
Chase Combining ◽  
High Order Modulation

Hybrid automatic repeat request (HARQ) is used in high-speed uplink packet access (HSUPA) to increase the data rate. Chase combining is the simplest of HARQ algorithms. It provides a time diversity and requires a small memory. In this paper, we propose a technique to increase the chase combining efficiency. In this method, HARQ transmissions are seen as additional receive antennas which are jointly combined at chip-level using a space-time linear minimum square error (LMMSE). We demonstrate that the chase combining diversity gain is considerably increased especially for high-order modulation.

Joint Angular and Time Diversity of Multi-Antenna CDMA Systems in Wireless Fading Channels

2011 ◽  
Vol 1 (1) ◽  
pp. 1-14
Author(s):  
Feng She ◽  
Hsiao Hwa Chen ◽  
Hongyang Li
Keyword(s):  
Fading Channels ◽  
Performance Improvement ◽  
Multipath Fading ◽  
Antenna System ◽  
Space Time ◽  
Diversity Gain ◽  
Multipath Fading Channel ◽  
Time Diversity ◽  
Time Domains ◽  
Code Division Multiple

In this paper, a multi-antenna based receiver structure for direct sequence code division multiple access (DS/CDMA) system is proposed. The proposed scheme exploits the excellent time resolution of a CDMA RAKE receiver and uses an antenna array beamforming structure to resolve multipath returns in both angular and time domains. A much higher diversity gain than that based only on the time domain diversity can be achieved. This work suggests a new space-time diversity paradigm, namely angular-time diversity, which differs from traditional Alamouti-type space-time coded schemes. The impairments caused by multipath and multiuser interference are analyzed. The performance of the proposed receiver in multipath fading channel is explicitly evaluated. An expression for uncoded system bit error probability is derived. Simulation results show the performance improvement in terms of BER due to the use of multi-antenna in the receiver, and the results illustrate that the multi-antenna based receiver works effectively in resolving multipaths in both angular and time domains to achieve performance improvement due to angular and time diversity gain provided by the multi-antenna system.

Joint Angular and Time Diversity of Multi-Antenna CDMA Systems in Wireless Fading Channels

2013 ◽  
pp. 1-14
Author(s):  
Feng She ◽  
Hsiao Hwa Chen ◽  
Hongyang Li
Keyword(s):  
Fading Channels ◽  
Performance Improvement ◽  
Antenna System ◽  
Space Time ◽  
Diversity Gain ◽  
Multipath Fading Channel ◽  
Time Diversity ◽  
Time Domains ◽  
The Time Domain ◽  
Array Beamforming

In this paper, a multi-antenna based receiver structure for direct sequence code division multiple access (DS/CDMA) system is proposed. The proposed scheme exploits the excellent time resolution of a CDMA RAKE receiver and uses an antenna array beamforming structure to resolve multipath returns in both angular and time domains. A much higher diversity gain than that based only on the time domain diversity can be achieved. This work suggests a new space-time diversity paradigm, namely angular-time diversity, which differs from traditional Alamouti-type space-time coded schemes. The impairments caused by multipath and multiuser interference are analyzed. The performance of the proposed receiver in multipath fading channel is explicitly evaluated. An expression for uncoded system bit error probability is derived. Simulation results show the performance improvement in terms of BER due to the use of multi-antenna in the receiver, and the results illustrate that the multi-antenna based receiver works effectively in resolving multipaths in both angular and time domains to achieve performance improvement due to angular and time diversity gain provided by the multi-antenna system.

scholarly journals Penggelaran Teknologi HSPA+ di Indonesia

2017 ◽  
Vol 1 (2) ◽  
pp. 96 ◽  
Author(s):  
Rahmad Hidayat
Keyword(s):  
High Speed ◽  
Multiple Input Multiple Output ◽  
High Order ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Packet Access ◽  
High Order Modulation

Akses data kecepatan lebih tinggi melalui jalur nirkabel memungkinkan dilayani oleh teknologi High Speed Packet Access Evolved (HSPA+). HSPA+ mampu meningkatkan kemampuan broadband mobile dengan kecepatan data sampai 42 Mbps dengan latensi dan delay yang rendah . Kemampuan ini diperoleh dariadanya penambahan teknologi HOM (High Order Modulation), 2x2 MIMO(Multiple Input Multiple Output) dan DTX / DRX (Discontinuous Transmissionand Reception) pada platform WCDMA. HSPA+ merupakan evolusi HSPAyang memungkinkan peningkatan upgrade dengan biaya relatif lebih rendah.Tulisan ini akan mendeskripsikan spesifikasi teknologi HSPA+ dan peluangnyayang cukup besar untuk digelar bagi peningkatan infrastruktur Information andCommunication Technology (ICT) di Indonesia.

A Novel HARQ for Space-Time Diversity in MIMO System

2010 ◽  
Vol 32 (4) ◽  
pp. 794-798
Author(s):  
De-sheng Wang ◽  
Hong-zi Lin ◽  
Guang-xi Zhu
Keyword(s):  
Mimo System ◽  
Space Time ◽  
Time Diversity
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