Clarke Malcolm, Mars Maurice
1 School of Information Systems, Computing, and Mathematics, Brunel University , Uxbridge, United Kingdom .
Telemed J E Health. 2015 Feb;21(2):115-9. doi: 10.1089/tmj.2014.0079. Epub 2014 Jun 13.
We investigated the use of third-generation (3G) mobile communications to provide telehealth services in remote health clinics in rural KwaZulu-Natal, South Africa.
We specified a minimal set of services as our use case that would be representative of typical activity and to provide a baseline for analysis of network performance. Services included database access to manage chronic disease, local support and management of patients (to reduce unnecessary travel to the hospital), emergency care (up to 8 h for an ambulance to arrive), e-mail, access to up-to-date information (Web), and teleclinics. We made site measurements at a representative set of health clinics to determine the type of coverage (general packet radio service [GPRS]/3G), its capabilities to support videoconferencing (H323 and Skype™ [Microsoft, Redmond, WA]) and audio (Skype), and throughput for transmission control protocol (TCP) to gain a measure of application performance.
We found that none of the remote health clinics had 3G service. The GPRS service provided typical upload speed of 44 kilobits per second (Kbps) and download speed of 64 Kbps. This was not sufficient to support any form of videoconferencing. We also observed that GPRS had significant round trip time (RTT), in some cases in excess of 750 ms, and this led to slow start-up for TCP applications.
We found audio was always so broken as to be unusable and further observed that many applications such as Web access would fail under conditions of very high RTT. We found some health clinics were so remote that they had no mobile service. 3G, where available, had measured upload speed of 331 Kbps and download speed of 446 Kbps and supported videoconferencing and audio at all sites, but we frequently experienced 3G changing to GPRS. We conclude that mobile communications currently provide insufficient coverage and capability to provide reliable clinical services and would advocate dedicated wireless services where reliable communication is essential and use of store and forward for mobile applications.
我们研究了利用第三代（3G）移动通信技术在南非夸祖鲁 - 纳塔尔省农村地区的偏远健康诊所提供远程医疗服务。
我们指定了一组最少的服务作为我们的用例，这些服务应代表典型活动，并为网络性能分析提供基线。服务包括用于管理慢性病的数据库访问、患者的本地支持与管理（以减少不必要的医院就诊）、紧急护理（救护车到达前长达8小时）、电子邮件、获取最新信息（网络）以及远程诊所服务。我们在一组具有代表性的健康诊所进行了现场测量，以确定覆盖类型（通用分组无线服务[GPRS]/3G）、其支持视频会议（H323和Skype™[微软，华盛顿州雷德蒙德]）和音频（Skype）的能力，以及传输控制协议（TCP）的吞吐量，以衡量应用性能。
我们发现，没有一家偏远健康诊所拥有3G服务。GPRS服务的典型上传速度为每秒44千比特（Kbps），下载速度为64 Kbps。这不足以支持任何形式的视频会议。我们还观察到GPRS的往返时间（RTT）很长，在某些情况下超过750毫秒，这导致TCP应用程序启动缓慢。
我们发现音频总是严重卡顿以至于无法使用，并且进一步观察到许多应用程序，如网络访问，在RTT非常高的情况下会失败。我们发现一些健康诊所非常偏远，以至于没有移动服务。在有3G服务的地方，测量得到的上传速度为331 Kbps，下载速度为446 Kbps，并且在所有站点都支持视频会议和音频，但我们经常遇到3G切换到GPRS的情况。我们得出结论，目前移动通信提供的覆盖范围和能力不足以提供可靠的临床服务，并且主张在可靠通信至关重要的情况下使用专用无线服务，并对移动应用程序采用存储转发方式。
