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Optimized Inter Prediction for H.264 Video Codec

Bernatin T., Sundari G., Anselin Nisha Sahaya, Godwin Premi M. S.

International Journal of Electronics and Telecommunications

2021

Vol. 67, No. 2

309--314

High definition video transmission is one of the prime demands of modern day communication. Changing needs demand diverse features to be offered by the video codec standards, H.264 fits to these requirements for video compression. In this work, an attempt has been made to optimize the inter prediction along with improved intra prediction to ensure the minimal bit rates thereby reduction in the channel bandwidth, which is required in most of the wireless applications. In intraprediction, only DC prediction mode is chosen out of 9 modes with 4*4 luma blocks that reduces the coding complexity towards optimal logic utilization in order to support typical FPGA board for hardware implementation. Most significantly, Inter prediction is carried out utilizing the M9K blocks efficiently with proper timing synchronization to reduce the latency in the encoding operation. Experimental set up comprising of two Altera DE2-115 boards connected through Ethernet cable demonstrated the video transmission. These optimized intra prediction and inter prediction stages resulted in significant improvement in the video compression possessing good subjective quality and increased video compression.

Joint Timing Synchronization and Channel Estimation Using Perfect Sequence in Uplink Time Domain Synchronous OFDMA

Lakshmanan M., Mallick P.S., Nithyanandan L.

International Journal of Electronics and Telecommunications

2016

Vol. 62, No. 3

225--229

Time Domain Synchronous Orthogonal Frequency Division Multiple Access (TDS-OFDMA) is used in mobile broadband wireless access scheme in uplink transmission. This leads to multiple user interference due to timing offset and frequency offset. In this paper, the effect of timing offset and channel estimation in mobile broadband system is analysed. Time-space two dimensional structure is used in TDS-OFDMA and perfect sequence is used for guard interval to achieve perfect timing synchronization and channel estimation for each user. Simulations are performed for timing synchronization and channel estimation using perfect sequence under Urban channel, Indoor Office B channel and HIPER LAN-A channel. Simulation results show that the timing synchronization is achieved and channel estimation performance using perfect sequence is better than CAZAC and PN Sequences.

Timing Synchronization and Frequency Offset Estimation for OFDMA/TDD Mode in Downlink of IEEE 802.16-2004

Rahbari F., Bakhshi H. R.

International Journal of Electronics and Telecommunications

2012

Vol. 58, No. 3

261-266

Timing and frequency synchronization are the important task in receiver. This paper proposes a timing synchronization and carrier frequency offset (CFO) estimation algorithm for orthogonal frequency division multiple access (OFDMA) downlink in IEEE 802.16e standard. This method has high performance and estimates CFO. The proposed scheme utilizes the conjugate symmetry property of preamble structure. Simulations are conducted for AWGN and multipath channels to demonstrate the performance of the proposed timing metric. Our proposed method can achieve reasonable performance at low SNR.