Digital Wireless Standards (Data)

As you can see there are a multitude of wireless cellular and data standards in various countries across the world. After divining into the more “techie” pieces of the wireless spectrum, we will focus on more conceptual definitions and applications.


Japan (PDC, PHS)

PDC: Personal Digital Cellular is the 2G TDMA-based protocols used in Japan, owned by NTT DoCoMo. PDC services operate in the 800 and 1500 MHz bands. PDC is the Japanese equivalent of GSM but is incompatible with other systems. It is operated by NTT DoCoMo, as well as by all the other Japanese operators, but the technology was developed by NTT DoCoMo. Previously known as PHP (Personal HandyPhone) and Japanese Digital Cellular (JDC)
PHS: Personal Handyphone System is the Japanese version of the U.S.’s PCS (Personal Communications Services) with two key differences. It’s not as powerful as PCS. You can’t use a PHS phone in a rapidly moving vehicle, since there is no cell-handoff (i.e. it won’t move you from one cell to another) and thus, if you move outside your cell with PHS, you lose connection. PHS is a perfect mobile phone for pedestrians in high density cities like Tokyo, as long as they don’t move around a lot during the course of a call.

US (CDPD (AMPS), ARDIS, 802.11)

CDPD (AMPS): Cellular Digital Packet Data is a radio technology that supports the transmission of packet data at speeds of up to 19.2Kbps over the existing analog AMPS (Advanced Mobile Phone Service) cellular network, with appropriate CDPD upgrades. The data is structured in packets that are transmitted during pauses in cellular phone conversations, thereby avoiding issues of developing an overlay cellular network for data communications. Estimates suggest that as much as 20%-30% of an AMPS network is idle, even during periods of peak usage. This idle capacity is due to short pauses between the point in time at which you disconnect your circuit-switched cellular telephone conversation and the time when someone else seizes that same radio channel to place a call. Idle capacity also is created when you are “handed-off” from one cell to another as your travel through the area of coverage in your vehicle. While 19.2 Kbps transmission rates are possible, throughput commonly drops to 2.4 Kpbps or so during periods of peak usage.

ARDIS: A public data communications wireless network that allows people carrying hand-held devices to send and receive short data messages. Such messages might be from a sheriff standing in the street searching his department’s data base for unpaid parking tickets. ARDIS network was purchased by Motient Corporation, formerly American Mobile, in 1998. The network is the largest packet data network in the US and provides packet data services using the DataTAC protocol. ARDIS was originally jointly owned by Motorola and IBM. It was an outgrowth of a network originally created for IBM service technicians.


802.11 (b&a are the most important, therefore we will focus on those)

1) 802.11b is now the most common wireless local area network. 802.11b is now installed in offices, airports, coffee shops, hotels, boardrooms, and homes. Many laptops now come with 802.11b wireless transmit and receive electronics built-in. Also known as Wi-Fi, 802.11b is a low power wireless system so the closer you are to a transmitter, the faster it will be. This is roughly what you’ll get at Wireless operating range (indoors):
a. 100 feet at 11 Mbps
b. 165 feet at 5.5 Mbps
c. 230 feet at 2 Mbps
d. 300 feet at 1 Mbps

2) 802.11a is an updated, bigger, better, faster version of 802.11b. The newer 802.11a supports speeds up to 54 Mbps and runs in a 300-Mhz allocation in the 5 Ghz range, which was allocated by the FCC in support of the Unlicensed National Information Infrastructure.


Europe (GSM, HiperLan)
GSM (please refer to past WotD)

HiperLan: High performance radio local area network. Developed by the European Telecommunications Standards Institute (ETSI), HiperLan is a set of WLAN communication standards used chiefly in European countires. HiperLAN is similar to the IEE 802.11 WLAN standards used in the U.S. There are 2 types of HiperLAN:

1) HiperLAN/1: provides communications at up to 20 Mbps in the 5 Ghz band
2) Hiper LAN/2: provides communications at up to 54 Mbps in the 5 Ghz band

According to ETSI, HiperLAN/2 marks a significant milestone in the development of a combined technology for broadband cellular short-range communications and wireless LANs which will provide performance comparable with that of wired LANs.