Technical standards for the PHS air interface are stipulated under RCR STD-28 by the Association of Radio Industries and Businesses (ARIB). ARIB recently made a series of wide-ranging revisions to this, which it published as RCR STD-28 Version 3.3.

Among the revisions was the addition of a new type of air interface in FWA (Fixed Wireless Access) system enabling provision of ISDN and leased line services via the system. Also included were descriptions concerning the transmission of the reason for not indicating caller ID and call forwarders' ID, as well as updates aimed at maintaining consistency with the recently revised Telecommunication Technology Committee (TTC) standards. Version 3.3 in English (the Japanese version is official) is available at 58,000 yen from ARIB. Japanese consumption tax and shipping are not included in this price.

1. Revisions concerning FWA system

1) Alteration of the term WLL to FWA

The International Telecommunication Union's Radiocommunication Sector (ITU-R) recently issued ITU-R Recommendation F.1399, which describes new wireless access terminology adopted by ITU-R. Based on this, the term WLL (Wireless Local Loop) in RCR STD-28 was replaced by FWA.

2) Addition of a new type of air interface in FWA system for providing ISDN and leased line services

In the previous RCR STD-28 Version 3.2, the public PHS air interface (used mainly for providing analog telephony service) was fully applied to FWA system. The latest version now includes a new type of air interface that makes ISDN and leased line services available via the FWA system. With this update, the communication channels are first set up by using the public PHS air interface to establish the entire network. As a result, respective control information in layers 2 and 3 is transparently conveyed through these channels. For instance, where an ISDN service is of the 2B+D type, one 32 kbit/s communication channel is assigned to D channel and two 64 kbit/s communications channels are assigned to two B channels (B1 and B2).

3) Addition of 64 kbit/s PCM voice and 3.1 kHz audio bearer services

The 64 kbit/s PCM (pulse code modulation) voice and 3.1 kHz audio bearer services, typical of ISDN bearer service via B channels, were added to the latest version. The 64 kbit/s unrestricted digital bearer service was already included in the previous version.

2. Revisions regarding transmission of the reason for not indicating caller ID

An appendix was added to the latest version, which deals with supplementary services to be provided using functional operations defined by entities other than ARIB. The appendix describes how these services should be dealt with in RCR STD-28 as well as the way to cite their sources. The first item included in the appendix was the transmission of the reason for not indicating caller ID (telephone number).

3. Revisions regarding the transmission of call forwarders' ID

A new function was added to the latest version; when an incoming call is forwarded to a target PHS terminal, this function allows the call forwarder's ID to be transmitted to the target terminal over the PHS air interface. In other words, the receiver of the forwarded call can check the call forwarder's ID (telephone number) on the display.

4. Revisions for maintaining consistency with TTC standards