2.1 What is ICT?
In Japan, ECG monitor, peripheral saturation of blood oxygen, cardiac defibrillator, and other ME equipments have been already installed in 4800 ambulances. The purpose of in-ambulance ICT is to improve emergency rescue quality by transmitting patient data and ambulance GPS data to the triage center automatically, with no inconvenience to or undue effort by the crew. Ideally, ICT would connect the patient monitor online with TCP/IP and record crew activities automatically and electronically. In reality, time standards for the ambulance clock, cardiograph, and communication devices are not synchronized in Japan, and rescue crews must match these manually every morning. Synchronizing these devices would be a simple matter if the devices were linked via TCP/IP connections.
2.2 The Third Generation (3G) Mobile Phone
Some believe communications with moving ambulances should be based on the 3G mobile phone network (Curry & Harrop, 1998; Istepanian, Jovanov, & Zhang, 2004; Lee, Kim, Hwang, & Kim, 2008; Pavlopoulos, Kyriacou, Berler, Dembeyiotis, & Koutsouris, 1998). Is this correct? Is the 3G mobile phone network good enough to ensure multi-path high-speed transmission from fast-moving ambulances? The answer is no, even in Japan, where a 3G network is established nationwide.
Multi-Path Communication
This technology is not yet established. If the base station antenna is located very close to the mobile terminal and communication occurs in line-of-sight mode (Nakagami-Rice fading), communications will be reliable and stable and throughput close to nominal values. But in non-line-of-sight mode (Rayleigh fading), communication is not reliable under multi-path conditions, resulting in inadequate throughput. Maintaining a 384kbps connection rate (the FOMA uplink standard) during transmission from a moving car is quite difficult. None of the various studies involving transmissions from ambulances using the 3G network have led to introduction of a practical system.
Service area problems: The number of base stations for the NTT DoCoMo 3G FOMA Service is now at around 3,200 in the Kanto-Koshinetsu area and 10,700 across the nation, with service areas expanding. The population coverage is about 98% nationwide as of the end of December 2007. This coverage, however, counts all city/village citizens when their local administration office exists in a service area (Figure 1). Undoubtedly, this approach counts mountainous areas and remote islands that are actually located outside service areas. Since mobile phone carriers follow profit-oriented market dynamics with cream-skimming policies (shedding unprofitable areas), they will not invest money to construct base stations in these areas. Even with the advent of the 4G network, they will likely focus on urban areas while shortchanging rural populations.
Figure 1. NTT DoCoMO’s 3G coverage (FOMA September 2009)