无线多接入信道的能量极限分析

能效优先的传输理论和技术对于下一代无线网络的设计具有重要的意义。本项目应用多用户信息论,研究无线多接入信道能效与谱效之间的折中关系,及其能量效率极限等理论问题。本项目将从理论上研究多接入信道的能量极限,从而提升移动终端电池的续航能力,增强用户体验,为下一代绿色无线通信系统的设计提供新思想、新技术和新方法。

基于WLAN的宽带无线多接入解决方案

数据业务已越来越多地步人移动领域，手机体积的日趋缩小、数据处理能力的日趋提高以及3G无线广域网(WAN)的广泛部署均人大提高了数据业务的便捷性与可用性。图1显小了移动通信的演进模式。尢线局域网(WLAN)和蓝牙技术等补充技术也进一步增强了数据业务的接入与交付能力。在当今多种接人技术(multi—access)共存的时代，用户希望在多个接入连接上得到连续、优化的作业连接(service-session)。此外，用户还希望能够获得定制服务，这标志着“始终最佳连接(ABC)”时代的来临。

新一代新闻直播指挥系统的研究

本文比较了国内外基于公网的指挥系统技术,总结整理了新闻直播指挥系统的技术需求,初步形成了整体解决技术方案。探讨了各种技术实现手段的特点和在本系统中的适用性,同时对多种接入技术同时无缝接入系统、多种通信手段的同时使用以及实时语音编码技术进行了阐述。本文提出了一种融合各种技术手段的新闻直播指挥系统方案,并简要探讨其中使用的关键技术。

新闻制作直播网络系统设计与分析

本文比较了国内外基于公网的指挥系统技术,总结了新闻直播指挥系统的技术需求,初步形成了整体解决技术方案。探讨了各种技术实现手段的特点和在本系统中的适用性,对多种接入技术无缝接入系统、多种通信手段的同时使用以及实时语音编码技术进行了阐述。提出了一种融合各种技术手段的新闻直播指挥系统方案,并简要探讨其中使用的关键技术。

Qo E-based resource allocation protocols in cognitive OFDMA network with hybrid model

A resource allocation protocol is presented in an orthogonal frequency division multiple access （OFDMA） cognitive radio （CR） network with a hybrid model which combines overlay and underlay models. Without disrupting the primary user （PU） transmissions, the overlay model allows the secondary user （SU） to utilize opportunistically the idle sub-channels; the underlay model allows the SU to occupy the same sub-channels with PU. The proposed protocols are designed for maximizing the quality of experience （QoE） of CR users and switching dynamically between the overlay and underlay models. QoE is measured by the mean opinion score （MOS） rather than simply fulfilling the physical and medium access control （MAC） layer requirements. The simulations considering the file transfer and video stream services show that the proposed resource allocation strategy is spectrum efficient.

Fair subcarrier-power allocation scheme for multiuser multicarrier systems

The main objective of multiuser orthogonal frequency division multiple access(MU-OFDM) is to maximize the total system capacity in wireless communication systems. Thus, the problem in MU-OFDM system is the adaptive allocation of the resources(subcarriers, bits and power) to different users subject to several restrictions to maximize the total system capacity. In this work, a proposed subcarrier allocation algorithm was presented to assign the subcarriers with highest channel gain to the users. After the subcarrier allocation, subcarrier gain-based power allocation(SGPA) was employed for power and bit loading. The simulation results show that the proposed subcarrier-power allocation scheme can achieve high total system capacity and good fairness in allocating the resources to the users with slightly high computational complexity compared to the existing subcarrier allocation algorithms.

A novel spectrum borrowing scheme in integrated 3G/WLAN networks

In the heterogeneous wireless networks of the next generation, a large number of different radio access technologies will be integrated into a common network. This paper considers optimizing the utilization of spectrum resource in heterogeneous environment consisting two different networks： wireless local area network （WLAN） and time division-synchronous code division multiple access （TD-SCDMA） network. An optimal joint spectrum borrowing scheme maximizing overall network revenue is proposed with quality of service （QoS） constraints over both the WLAN and the TD-SCDMA cellular networks. Simulation results illustrate that system revenue earned in the proposed joint spectrum borrowing scheme is significantly larger than the case when individual networks are optimized independently.

Dynamic Time Division Multiple Access Algorithm for Industrial Wireless Hierarchical Sensor Networks

Industrial wireless sensor networks adopt a hierarchical structure with large numbers of sensors and routers. Time Division Multiple Access (TDMA) is regarded as an efficient method to reduce the probability of confliction. In the intra-cluster part, the random color selection method is effective in reducing the retry times in an application. In the inter-cluster part, a quick assign algorithm and a dynamic maximum link algorithm are proposed to meet the quick networking or minimum frame size requirements. In the simulation, the dynamic maximum link algorithm produces higher reductions in the frame length than the quick assign algorithm. When the number of routers is 140, the total number of time slots is reduced by 25%. However, the first algorithm needs more control messages, and the average difference in the number of control messages is 3 410. Consequently, the dynamic maximum link algorithm is utilized for adjusting the link schedule to the minimum delay with a relatively high throughput rate, and the quick assign algorithm is utilized for speeding up the networking process.

Multi-service small-cell cloud wired/wireless access network based on tunable optical frequency comb

In this paper,we demonstrate a novel multi-service wired/wireless integrated access architecture of cloud radio access network(C-RAN) based on radio-over-fiber passive optical network(RoF-PON) system,which utilizes scalable multiple-frequency millimeter-wave(MF-MMW) generation based on tunable optical frequency comb(TOFC).In the baseband unit(BBU) pool,the generated optical comb lines are modulated into wired,RoF and WiFi/WiMAX signals,respectively.The multi-frequency RoF signals are generated by beating the optical comb line pairs in the small cell.The WiFi/WiMAX signals are demodulated after passing through the band pass filter(BPF) and band stop filter(BSF),respectively,whereas the wired signal can be received directly.The feasibility and scalability of the proposed multi-service wired/wireless integrated C-RAN are confirmed by the simulations.