Limiting the Holding Time Considering Emergency Calls in Mobile Cellular Phone Systems during Disasters
Limiting the Holding Time Considering Emergency Calls in Mobile Cellular Phone Systems during Disasters
复制标题
考虑到灾害期间移动蜂窝电话系统的紧急呼叫，限制保持时间
DOI：
10.1093/ietcom/e89-b.1.57
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
K. Okada
中科院分区：
文献类型：
--
作者：
K. Okada
在毁灭性的自然灾害期间，许多人想打电话去灾区查看家人和朋友的情况，但由于无线电频率资源有限，许多人在移动蜂窝系统上的呼叫尝试被阻止。为了减少呼叫阻塞，并使尽可能多的人能够访问移动蜂窝系统，对每个呼叫的保持时间进行了限制[1]、[2]。然而，在灾难期间，紧急呼叫，例如消防、救护车或警察服务的呼叫也极有可能增加，重要的是这些呼叫的保持时间不受限制。提出了一种限制呼叫保持时间的方法，以便在考虑普通呼叫者需求的同时为紧急呼叫做好准备。在这种称为HTL-E方法的方法中，根据拨打给进行紧急呼叫的特定终端的号码或预先给出的终端号码，将所有呼叫分类为紧急呼叫或其他呼叫，并且仅限制其他呼叫的保持时间。通过计算机模拟对HTL-E方法的性能特征进行了评估。结果表明，它显著降低了切换时的阻塞率和强制终止率，而没有减少紧急呼叫的保持时间。紧急呼叫和其他呼叫的阻塞率几乎相同。此外，HTL-E方法灵活地处理紧急呼叫需求的波动。还提出了一种估计其他呼叫的保持时间限制的简单方法，该方法在呼叫需求增加的时段将紧急呼叫和其他呼叫的阻塞率降低到正常速率。该方法的计算结果与模拟结果吻合较好。
During devastating natural disasters, numerous people want to make calls to check on their families and friends in the stricken areas, but many call attempts on mobile cellular systems are blocked due to limited radio frequency resources. To reduce call blocking and enable as many people as possible to access mobile cellular systems, placing a limit on the holding time for each call has been studied [1], [2]. However, during a catastrophe, emergency calls, e.g., calls to fire, ambulance, or police services are also highly likely to increase and it is important that the holding time for these calls is not limited. A method of limiting call holding time to make provision for emergency calls while considering the needs of ordinary callers is proposed. In this method, called the HTL-E method, all calls are classified as emergency calls or other according to the numbers that are dialed or the terminal numbers that are given in advance to the particular terminals making emergency calls, and only the holding time of other calls is limited. The performance characteristics of the HTL-E method were evaluated using computer simulations. The results showed that it reduced the rates of blocking and forced call termination at handover considerably, without reducing the holding time for emergency calls. The blocking rate was almost equal for emergency and other calls. In addition, the HTL-E method handles fluctuations in the demand for emergency calls flexibly. A simple method of estimating the holding-time limit for other calls, which reduces the blocking rate for emergency and other calls to the normal rate for periods of increased call demand is also presented. The calculated results produced by this method agreed well with the simulation results.