Rate selection based medium access control for full-duplex asymmetric transmission

The realization of full-duplex wireless communication is predictable. And asymmetric transmission is a practical and low-cost application scenario, where full-duplex access point (FD_AP) can communicate with two users simultaneously to receive and send packets. While, in an asymmetric transmission, the transmit power of uplink sender decides the uplink and downlink rates because of the inter-client interference, which accordingly restricts the throughput. Besides, the size of packets in uplink and downlink is generally unequal. Therefore, a WIFI network with a FD_AP and half-duplex users is studied in this paper, and a medium access control (MAC) protocol based on power control and rate selection (PCRS) is proposed. PCRS MAC employs a received signal strength based rate selection strategy to select different rates and power for uplink and downlink transmission. Then, FD_AP can establish efficient and reliable full-duplex asymmetric transmission. Simulation results show that PCRS can improve the throughput and the probability of successful asymmetric communication as compared to the distributed coordination function (DCF) and a simple full-duplex MAC protocol without PCRS. Besides, PCRS MAC also maintains a high level of fairness.

     

Managing IP services over a PACS Packet Network

We have developed a system and network architecture to provide IP services in the Personal Access Communications System (PACS). IP datagrams are delivered to PACS users through the PACS packet-mode data service, achieving more efficient usage of wireless resources and supporting multimedia applications such as MBone audio and video. The architecture presented in this article augments the PACS voice network with IP routers and backbone links, called the PACS Packet Network (PPN), and is connected to the global Internet via gateways. Compared to the cellular digital packet data (CDPD) network, which employs its own network-layer mobility protocol and thus supports roaming within the CDPD network only, we have incorporated Mobile IP into the PACS handoff mechanism to further achieve global IP mobility. We have also developed native PACS multicast and a group management scheme to efficiently handle dynamic IP multicast and MBone connectivity. These features seamlessly integrate PACS into the global Internet and provide standard-conforming IP services with global mobility     

多用户多载波无线携能通信系统的上下行联合资源分配

无线携能通信(SWIPT)技术是解决无线网络能量受限问题的有效方法,该文研究一个由基站(BS)和多用户组成的多载波SWIPT系统,其上行和下行链路均采用正交频分复用(OFDM)技术。在下行链路中,基站向用户同时进行信息与能量传输;在上行链路中,用户利用从基站接收的能量向基站回传信息。该文以最大化上下行加权和速率为目标,联合优化上行和下行的子载波分配和功率分配,提出基于拉格朗日对偶法和椭球法的最优联合资源分配算法。计算机仿真结果证实了该算法的有效性。     

Performance of Uplink NOMA with User Mobility Under Short Packet Transmission

Wireless Personal Communications - The scenario of an uplink two-user non-orthogonal multiple access (NOMA) communication system is analytically studied when it operates in the short packet...     

Performance of personal access communications system-unlicensed B

The FCC has allocated the band between 1920 MHz and 1930 MHz for unlicensed personal communications services (UPCS) using isochronous or circuit operation. The UPCS spectrum is between the licensed PCS spectrum bands of 1850-1910 MHz and 1930-1990 MHz. Terminal interoperability in both the UPCS spectrum on private indoor wireless systems and the licensed spectrum on public PCS systems is desirable and encouraged by the FCC. This paper presents a port channel assignment process for the personal access communications system-unlicensed B (PACS-UB) which abides by the FCC etiquette for UPCS and discusses the corresponding uplink and downlink performance. Uplink power control is employed to improve the uplink performance. PACS-UB has a high degree of commonality with licensed PACS to permit economical licensed/unlicensed terminals and common network services. The results of our simulation show that, at 1% to 2% blocking probability, 99% of downlink local-mean signal-to-noise plus interference ratio (SINR) values are above 17 dB for a 10 to 20 m port separation. For a three-dimensional office environment, the uplink limits the SINR performance, however, with uplink power control, a 5.5 to 7 dB improvement in the uplink SINR can be achieved even for high traffic load     

Joint utility function-based scheduling for two-way communication services in wireless networks

A type of joint utility function-based scheduling is proposed for two-way communication services in wireless networks. The scheduling of uplink and downlink services is done jointly so that the base station selects a user efficiently and fairly while considering the channel state of both the uplink and the downlink. Because a user generally has two communication links, an uplink and a downlink, the overall satisfaction with a communication service can be formulated as the sum of the quality of the uplink and downlink services. However, most of the previous types of scheduling for the uplink and downlink were designed separately and independently. This paper proposes a joint scheduling algorithm for integrated uplink and downlink services: a base station selects a user while simultaneously considering both the uplink channel state and the downlink channel state. An analytical model is developed for the purpose of determining the scheduling metric, the system throughput, and the level of fairness. The numerical and computer simulation results show that in comparison with conventional proportional fair scheduling the proposed joint scheduling achieves a better throughput while satisfying the fairness among users.     

Self-subrating for voice/data in PCS

Bellcore Personal Access Communications System (PACS) provides the feature of using a single time-slot for two independent calls by the same user. This feature allows a simultaneous voice and data call from a single subscriber unit. This paper compares the performance of a PCS system with voice/data self-subrating (SSR) with a system without self-subrating (NSSR). We show that for the ranges of the input parameters we study, the blocking probability for NSSR is 76% higher than for SSR. For a PCS system engineered at 1% blocking probability, SSR carries 15.3% more offered load than NSSR.     

Interference cancellation for cellular systems: a contemporary overview

Cellular networks today are interference-limited and only becomes increasingly so in the future due to the many users that need to share the spectrum to achieve high-rate multimedia communication. Despite the enormous amount of academic and industrial research in the past 20 years on interference-aware receivers and the large performance improvements promised by these multi-user techniques, today's receivers still generally treat interference as background noise. In this article, we enumerate the reasons for this widespread scepticism, and discuss how current and future trends increases the need for and viability of multi-user receivers for both the uplink, where many asynchronous users are simultaneously detected, and the downlink, where users are scheduled and largely orthogonalized; but the mobile handset still needs to cope with a few dominant interfering base stations. New results for interference cancelling receivers that use conventional front-ends are shown to alleviate many of the shortcomings of prior techniques, particularly for the challenging uplink. This article gives an overview of key recent research breakthroughs on interference cancellation and highlights system-level considerations for future multi-user receivers.     

Energy-Efficient Uplink Resource Allocation Based on Game Theory in Cognitive Small Cell Networks

Wireless Personal Communications - In this paper, resource allocation for energy-efficient uplink communications in cognitive small cell networks is studied. We formulate the entire network energy...     

Lower Complex Resource Allocation Methodology based on Graph Theory and Index Matrix Rearrangement for OFDMA/MIMO-OFDMA Systems

Wireless Personal Communications - Resource allocation assigns subcarriers and power at the Base Station (BS) to different users, and is an important aspect in multiuser OFDMA downlink (DL)...     

Sum Ergodic Capacity Analysis Using Asymptotic Design of Massive MU-MIMO Systems

Wireless Personal Communications - This communication attempts to characterize the performance metrics of downlink Massive MU-MIMO systems impaired by cochannel interference and additive noise over...     

A unified wireless LAN architecture for real-time and non-real-timecommunication services

This paper addresses how to support both real-time and non-real-time communication services in a wireless LAN with dynamic time-division duplexed (D-TDD) transmission. With D-TDD, a frequency channel is time-shared for both downlink and uplink transmissions under the dynamic access control of the base station. The base station (1) handles uplink transmissions by polling mobiles in a certain order determined on a per-connection (per-message) basis for transmitting real-time (non-real-time) traffic from mobiles and (2) schedules the transmission of downlink packets. To handle location-dependent, time-varying, and bursty errors, we adopt the channel-state prediction, transmission deferment, and retransmission. We consider the problems of scheduling and multiplexing downlink packet transmissions, and polling mobiles for uplink transmissions depending on the channel state. We also establish conditions necessary to admit each new real-time connection by checking if the connection's delivery-delay bound can be guaranteed as long as the channel stays in good condition without compromising any of the existing guarantees. Last, the performance of the proposed protocol is evaluated to demonstrate how the protocol works and to study the effects of various parameters of the protocol     

Novel Fuzzy Based Crow Search Optimization Algorithm for Secure Node-to-Node Data Transmission in WSN

Wireless Personal Communications - This paper studies the performance of device-to-device (D2D)-enabled cellular network with D2D users reusing downlink resources of cellular links. The cellular...     

CDMA/TDD system for wireless multimedia services with trafficunbalance between uplink and downlink

This paper proposes a code division multiple access (CDMA) time division duplex (TDD) system for wireless multimedia services with traffic unbalance between uplink and downlink. In the proposed system, the number of uplink time slots in a TDD frame differs from that of downlink. Moreover, the difference can be reset by the network operator according to the traffic pattern. We evaluate the performance of the proposed system under multimedia environment using Markov analysis and computer simulation. The results show that the frequency utilization is maximized even when the uplink and downlink traffic volumes are unbalanced. This, in turn, reduces drastically the blocking rate of multimedia calls (connections) in the proposed system compared with that in the traditional CDMA systems where the uplink and downlink use equal bandwidth     

Downlink beamforming for DS-CDMA mobile radio with multimediaservices

Downlink beamforming is a promising technique for direct-sequence code-division multiple-access (DS-CDMA) systems with multimedia services to effectively reduce strong interference induced by high data rate users. A new downlink beamforming technique is proposed that converts the downlink beamforming problem into a virtual uplink one and takes into account the data rate information of all users. Since the main complexity of this method is due to the existence of multidelay paths, two simplified algorithms are suggested using an equivalent one-path channel vector to replace multipath channel vectors. Computer simulation results are given to evaluate the downlink capacity of DS-CDMA systems using a base station antenna array and the new algorithms proposed     

High-speed nondirective optical communication for wireless networks

The primary obstacles to high-speed communication, namely, shot noise from ambient light, high-capacitance photodiodes and multipath dispersion, are reviewed, and ways to counter them are demonstrated for a prototypical infrared system. The discussion is limited to the physical-layer issues involved in the design of a single high-speed optical link. The focus is on the downlink (from base station to portable), which is a more challenging problem technically than the uplink for two reasons. First, the complexity of the portable receiver is much more constrained than that of the base station, due to power consumption and cost restrictions. Second, the downlink data rates are likely to be much higher than the uplink rates, because downlink communication will include downloading large executable files and possibly video services, whereas uplink communication will be used for transferring working files and keyboard commands which tend to be much smaller     

A Weight-Based Resource Scheduling Algorithm for Uplink LTE-A Femtocell Network

Wireless Personal Communications - SC-FDMA is the most suitable option for the LTE-A uplink. Contiguity plagiarism characteristics are required for optimum channel scheduling in an SC-FDMA system....     

室内VLC-WiFi异构无线接入网络研究

对室内VLC-WiFi异构网络进行研究,提出了基本的组网结构及改进的切换策略.根据室内VLC-WiFi异构网络的特点,确定了上下行传输方案,即上行数据使用WiFi链路传输,下行数据使用VLC和WiFi链路传输.当下行VLC链路不可用时,提出了一种基于切换间隔和运动趋势的动态驻留时间算法.仿真结果表明,提出的切换算法与传统算法相比,在不增加乒乓效应的前提下提高了系统的命中率.     

Personal communications services

The history of the US Federal Communications Commission (FCC) examination of proposals to allocate radio frequency spectrum to a new and innovative range of services it calls personal communications services (PCS) is outlined. Personal communication networks (PCN), which will supply mobile two-way, mass-market communications services, the most advanced offering of the PCS area, and spectrum allocation for PCS are discussed. The results of a consumer market study of the potential for PCN services are also discussed     

A Crest Factor Reduction Scheme with Optimum Spacing Peak Cancellation for Intra-band Non-contiguous Carrier Aggregated OFDM Signals

Wireless Personal Communications - Recent development in communications have increased the demand of internet protocol (IP)-based multimedia conferencing services. Session initiation protocol (SIP)...