轻松旅途outgoing with Wireless

在路上、在野外、在风景里……在都市、在陌生的街上、在红绿灯的包围中……这些无线设备会是你最好的帮手和伙伴……     

玩在旅途最佳旅途手机游戏推荐

抽烟，是因为手指寂寞 某年的假期我在某地长途汽车站等人，说好时间却迟迟不见接我的人，百无聊赖。我第一次花了10块钱买了一包香烟。点燃烟，每根烟只抽一口，看蓝色的烟升起。     

旅途中的见闻

6月初，公司组织了一次旅行——张家界五日游。在这里我不想为张家界的风景大饰笔墨，虽然那的确是不可多见的风景。我想说的是在旅途中的一些人和事。     

旅途中的数码产品

这次婺源之旅因为有了众多的数码产品而变得与众不同。面对着独具特色的乡村美景。听着淳朴的水乡居民介绍风土人情，应用着最新的数码产品．享受着七天悠长的假期……这一切．让我们一扫城市生活与工作的紧张与疲惫。对于这些优秀的数码产品。不仅仅是应用而己．身处这最美的乡村．将手中使用的产品融入其中．这本身就是一幅动人心弦的画面。看看我们是如何让这些时髦产品和当地环境融合的吧。     

把旅途当课堂

你的孩子是否知道：这个世界除了满街的汽车和高高的楼房外,还有高山和森林;除了快餐店里金黄色的少校鸡块和鸡腿外,公鸡和母鸡是有五彩的羽毛,可以满处跑的;除了小熊维尼和机器猫外,自然界里,还存在无数的牛羊和飞鸟……     

旅途安全靠肖特--肖特采用玻璃光纤提高旅途安全性

目前大量新技术不断涌现,使驾驶变得轻松悠闲.DVD播放机使那些后座乘客-特别是孩子们-在长途旅行时兴致盎然;同时导航系统会给驾驶员提供如何尽快到达目的地的准确信息;最新的交通情况报告会自动集成到路程计划功能中,这样就能有效避开交通阻塞;移动电话使人们随时随地都能联系到驾车者……     

旅途安全靠肖特——肖特采用玻璃光纤提高旅途安全性

目前大量新技术不断涌现，使驾驶变得轻松悠闲。DVD播放机使那些后座乘客一特别是孩子们在长途旅行时兴致盎然；同时导航系统会给驾驶员提供如何尽快到达目的地的准确信息；最新的交通情况报告会自动集成到路程计划功能中，就能有效避开交通阻塞；移动电话使人们随时随地都能联系到驾车者……     

最理想的旅途战士

拥有双向DSP处理能力的Discovery^（TM）665蓝牙耳机将为你提供更清晰的通话音质．[编者按]     

旅途相伴 SAMSUNG L74 WIDE

如果你正在挑选一款适合旅行的数码相机，那么三星蓝调L74Wide自然是个好的选择。     

Adieu from the outgoing Editor-in-Chief

It has been a pleasure and an honor to serve for the last three years as Editor-in-Chief of the IEEE Transactions on Wireless Communications. This Transactions is clearly the leading journal in its field and continues to publish very high-quality, peer-reviewed original papers that advance the state of the art and applications in wireless communications.     

享受工作

厌倦了千篇一律的办公室格子间?讨厌的网线不知道又是哪里接触不良,全办公室都上不了网?你的老板也在头疼——又要换写字楼了,重新布线划格子分配座位,一大堆扯皮麻烦的事儿正等着他呢。“无线办公”这一正在被越来越多的公司采用的办公室组网方式,一劳永逸地解决了这些问题,并且总体成本更为便宜,维护成本更低,老板轻松,员工也轻松。OK,假设你已经身处无线办公室。有哪些产品能让工作更轻松,更事半功倍呢?     

欢乐影音

25年前,Sony WALKMAN的诞生使得个人便携式影音娱乐产品流行至今。今天,MP3随身听、MD、便携式DVD播放机、MP3手机、带影音播放功能的PDA等产品种类和数量都空前丰富,蔚为壮观,而在无线领域,无线广播和电视从二十世纪开始改变了人类的整个文化生态。哪怕是在今天,手机厂商们仍旧争先恐后地为手机加上收音机功能,并当作激动人心的卖点     

Wireless scheduling with hybrid ARQ

A model for downlink wireless scheduling is studied, which takes into account both user-channel conditions and retransmissions with packet combining hybrid [automatic repeat request (ARQ)]. Quality-of-service (QoS) requirements for each user are represented by a cost function, which is an increasing function of queue length. The objective is to find a scheduling rule that minimizes the average cost over time. We consider two scenarios: 1) the cost functions are linear, and packets arrive to the queues according to a Poisson process and 2) the cost functions are increasing, convex, and there are no new arrivals (draining problem). In each case, we transform the system model into a different model that fits into a framework for stochastic scheduling developed by Klimov. Applying Klimov's results, we show that the optimal schedulers for the transformed models in both scenarios are specified by fixed priority rules. Applying the inverse transformation in each case gives the optimal scheduling policy for the original problem. The priorities can be explicitly computed, and in the first scenario, are given by simple closed-form expressions. For the draining problem, we show that the optimal policy never interrupts the retransmissions of a packet. We also show that a simple myopic scheduling policy, called the U'R rule, performs very close to the optimal scheduling policy in specific cases. We present numerical examples, which compare the performance of the optimal scheduling rule with several heuristic rules.     

基于无线电台的电话延伸系统

现阶段在我军的边防部队装备有大量旧式模拟制无线电台,这些电台的信号质量较差,接口功能有限,无法满足部队对通信的要求。本系统通过研制扩展接口设备,将电话网通过无线电台延伸到值勤巡逻分队,使指挥员可通过电话与一线外出分队直接通信。通过使用PIC18F8720微处理器和DSP芯片实现了这个接口设备,从试验仿真和结果来看,达到了研制目的,并且研制出了样机交付部队使用。     

Downlink Wireless Packet Scheduling with Deadlines

Next-generation cellular wireless communication networks aim to provide a variety of quality-of-service (QoS)-sensitive packet-based services to downlink users. Included among these are real-time multimedia services, which have stringent delay requirements. Downlink packet scheduling at the base station plays a key role in efficiently allocating system resources to meet the desired level of QoS for various users. In this paper, we employ dynamic programming (DP) to study the design of a downlink packet scheduler capable of supporting real-time multimedia applications. Under well-justified modeling reductions, we extensively characterize structural properties of the optimal control associated with the DP problem. We leverage intuition gained from these properties to propose a heuristic scheduling policy, namely, Channel-Aware Earliest Due Date (CA-EDD), which is based on a "quasi- static" approach to scheduling. The per-time-slot implementation complexity of CA-EDD is only O(K) for a system with K downlink users. Experimental results show that CA-EDD delivers up to 50 percent of performance gains over benchmark schedulers. CA-EDD achieves these performance gains by using channel and deadline information in conjunction with application layer information (relative importance of packets) in a systematic and unified way for scheduling.     

Wireless Network Coding with Cooperative Diversity

In this paper we integrate the ideas of network coding and relays into an existing practical network architecture used in a wireless network scenario. Specifically, we use the COPE architecture to test our ideas. Since previous works have focused on the communication aspect at the physical layer level, we attempt to take it one step further by including the MAC layer. Our idea is based on information theoretic concepts developed by Shannon in order to reliably apply network coding to increase the net throughput.     

无线家居无限生活

一年半以前本刊曾有过一期特别策划——《享受无线未来》（2004年第4期），那时的未来，现在有多少变成了现实？有没有可能，现在就能让自己的生活从此“无线”？