Abstract
In this paper, a novel unequal error protection (UEP) technique is proposed for video streaming over multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems. Based on the concept of hierarchical quadrature amplitude modulation (HQAM) UEP and multi-antenna UEP, the proposed technique combines the relative protection levels (PLs) of constellation symbols and the differentiated PLs of the transmit antennas. In the proposed technique, standard square quadrature amplitude modulation (QAM) constellations are used instead of HQAM so that the QAM mapper at the transmitter side and the soft decision calculation at the receiver side remain unchanged, but the UEP benefit of HQAM is retained. The superior performance of the proposed technique is explained by the improved connections between data with various priorities and data paths with various PLs. The assumed video compression method is H.264/AVC, which is known to be commercially successful. The IEEE802.16m system is adopted as a data transmission system. With the aid of realistic simulations in strict accordance with the standards of IEEE802.16m systems and H.264/AVC video compression systems, the proposed technique HQAM-multi-antenna UEP is shown to improve the video quality significantly for a given average bit error rate when compared with previous techniques.
Highlights
Video streaming services, such as video conferencing, multimedia messaging, and video telephony, operating under unstable wireless channel environments present significant challenges [1]
unequal error protection (UEP) technique for video streaming over multiple-input multiple-output (MIMO)-orthogonal frequency-division multiplexing (OFDM) systems techniques in their present forms cannot be applied to contemporary mobile systems such as IEEE802.16m and LTE-A systems because normal square quadrature amplitude modulation (QAM) have been adopted in the standards
When MSB2 and LSB2 are 01 and 10, respectively, as in Fig 3(b), the four bits are mapped onto a complex symbol 1 − j3, according to the QAM constellation in Fig 2, and the complex symbol is transmitted from the second reliable antenna
Summary
Video streaming services, such as video conferencing, multimedia messaging, and video telephony, operating under unstable wireless channel environments present significant challenges [1]. In the previous works [6]–[8], only singleantenna systems were considered Multiple antennas at both transmitter and receiver sides can increase either the data transmission speed or the transmission reliability without requiring additional transmission power and (or) spectral bandwidth [9]. Yun et al proposed a UEP video-streaming technique that uses SM multiple antennas and a joint signal detection method [15]. Channel gains are estimated using the linear interpolation method; estimation errors are included in the considered systems, and the PHY packets of different priorities are detected using a joint detection technique such as QR-LRL, which uses the estimated channel gains. We deal with single-user MIMO systems, indicating that a resource block (allocated to a specific user) occupies all the spatial streams, and that the APP layer video data (prioritized and divided) originates from a single user
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