在高密度蜂窝车联网(cellular vehicle-to-everything,C-V2X)中,群集通信终端的有效阵列接入方法是多业务性能保障和有限频谱效率提升的前提。利用蜂窝车联网中终端计算能力,提出了信道自适应的业务接入机制。该机制由基站估计当前区域...在高密度蜂窝车联网(cellular vehicle-to-everything,C-V2X)中,群集通信终端的有效阵列接入方法是多业务性能保障和有限频谱效率提升的前提。利用蜂窝车联网中终端计算能力,提出了信道自适应的业务接入机制。该机制由基站估计当前区域通信密度,生成通信密度关联的接入类别限制(access class barring,ACB)因子,并在通信区域内广播;随后,车载通信终端根据接收基站广播信号的信干噪比(signal to interference plus noise ratio,SINR)和ACB因子计算自适应信道状态的接入概率,并比较接入概率和ACB因子。当接入概率大于ACB因子时,通信终端以最小接入概率从前导码池中随机选择一个前导码上传到基站,以获得与信道状态匹配的接入机会。仿真结果表明,在高密度通信状态下,与S-ALOHA协议和M2M-OSA方案相比,所提方案平均接入碰撞概率降低了约5%~20%,有效地减小了平均接入时延。展开更多
We propose a novel prioritized intra refresh method for the wireless video communication.The proposed method considers the characteristics of the human visual system,the error-sensitivity of the bitstream,and the stat...We propose a novel prioritized intra refresh method for the wireless video communication.The proposed method considers the characteristics of the human visual system,the error-sensitivity of the bitstream,and the state of the time-varying wireless channel jointly.An expected perceptual distortion model was used to adjust the intra refresh rate adaptively.This model consists of the perceptual weight map based on an attention model,the bit error probability map based on bitstream size,and the dynamic channel state information(CSI).Experimental results indicate that,compared with other intra refresh methods that consider only the content of the video or the CSI,the proposed method improves the average peak signal-to-noise ratio(PSNR) of the whole frame by about 0.5 dB,and improves the average PSNR of the attention-area by about 0.8 dB.展开更多
文摘在高密度蜂窝车联网(cellular vehicle-to-everything,C-V2X)中,群集通信终端的有效阵列接入方法是多业务性能保障和有限频谱效率提升的前提。利用蜂窝车联网中终端计算能力,提出了信道自适应的业务接入机制。该机制由基站估计当前区域通信密度,生成通信密度关联的接入类别限制(access class barring,ACB)因子,并在通信区域内广播;随后,车载通信终端根据接收基站广播信号的信干噪比(signal to interference plus noise ratio,SINR)和ACB因子计算自适应信道状态的接入概率,并比较接入概率和ACB因子。当接入概率大于ACB因子时,通信终端以最小接入概率从前导码池中随机选择一个前导码上传到基站,以获得与信道状态匹配的接入机会。仿真结果表明,在高密度通信状态下,与S-ALOHA协议和M2M-OSA方案相比,所提方案平均接入碰撞概率降低了约5%~20%,有效地减小了平均接入时延。
文摘We propose a novel prioritized intra refresh method for the wireless video communication.The proposed method considers the characteristics of the human visual system,the error-sensitivity of the bitstream,and the state of the time-varying wireless channel jointly.An expected perceptual distortion model was used to adjust the intra refresh rate adaptively.This model consists of the perceptual weight map based on an attention model,the bit error probability map based on bitstream size,and the dynamic channel state information(CSI).Experimental results indicate that,compared with other intra refresh methods that consider only the content of the video or the CSI,the proposed method improves the average peak signal-to-noise ratio(PSNR) of the whole frame by about 0.5 dB,and improves the average PSNR of the attention-area by about 0.8 dB.
