Report itu-r m. 2038 Technology trends
HDRPNs enabling technology
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- 1 Introduction
- 2 Technologies to support more efficient IP applications over mobile systems
6 HDRPNs enabling technologyAs the packet transfer rate becomes very high the radio channel transmission characteristics may be different than what would be optimum for a ubiquitous cellular system. These high transmission rate channels, that are probably asymmetric, would be well suited for a TDD implementation, see Annex 3, where the channel distortion of the received signal can be used to precondition the high rate transmission signals. This high rate packet capability may require a modified air interface tailored for this application, see Annex 9. The TDD structure is also very flexible and can provide several different data rates at the same time or rapidly reconfigure the entire capacity into a single channel. This flexibility is important since new users enter and leave the coverage areas very quickly. The TDD structure also allows the mobile uplink to access a reconfigured channel to transmit large files to the network. This reconfiguration can assign a large portion of the time slots to the uplink transmission, but when the transmission is completed the time slots can be instantly assigned to other users, probably downlink users. Since the uplink is not expected to be used as frequently as the downlink it is spectrally efficient to have the flexibility to reassign the same spectrum between uplink and downlink. With a FDD structure the uplink spectrum would have to be reserved to handle large data throughput even if it is only used occasionally. Reservations also help these reconfigurations and the location services capability can provide accurate reservation information. Antennas also play a major role in the ability to transmit high data rates. The energy from the node needs to be concentrated into a small area to increase the signal strength for the target receiver and to reduce the amount of interference to the rest of the region. Antenna systems such as adaptive antennas (see Annex 4 and Annex 5) distributed antennas11, (see also Annex 1) and intelligent cells12 as possible solutions for concentrating the transmitted energy into small areas. One possible solution for control of the process would require a network algorithm that searches for the addressee of the packet file and determines the approximate location and quarries that region looking for the addressee, see Annex 9. The response to this particular quarry will include a geographical location and cause a second answer to be sent approximately 10 s later. Both transmissions are needed to determine direction and velocity of travel. Using the position and velocity vector for a targeted mobile the system calculates the arrival time for the targeted mobile to reach the next high rate packet node. The system sends, utilizing the ubiquitous cellular network, a message telling the addressee such things as how long it will take before he receives the message, who the message is from, the length of the message and how much he will be charged for deliver of the message. The addressee is asked if he wants to receive the message. If the answer is yes a reservation13 is made and the packet is delivered by the next high rate node and the addressee is billed for delivery. The system needs to also implement a special algorithm to rapidly synchronize and transfer packets. Probably a special error correcting technique is needed for this relatively unique data transmission channel14 The mobile terminal will have to be an adaptive terminal to provide this premium service and interact with the HDRPN, but still have capability to function effectively in the cellular network. Fortunately there is much progress in the field of software defined radios, see Annex 6 and Annex 11. These radios will also benefit from the work in RF MEMS, see Annex 12, as an enabling technology for the future terminal. This is not expected to have much impact on the cost of the terminal over a normal high end IMT 2000 terminal. Annex 8 Internet technologies and support of IP applications over mobile systems 1 IntroductionCurrent IMT 2000 systems include IP-based conversational services carried over IP-based networks connected to related radio access technologies. The basis of IP-based conversational service is to provide the IMT 2000 terminal with IP support including IP addressing. This IP layer operates above the IP-based bearer services in the IMT 2000 networks (core network and radio access networks). When discussing IP requirements the above has to be kept in mind, so that support for all-IP conversational service and above applications are not mixed with network internal requirements related to the usage of IP for its internal usage. It should then be remembered that the networks are defined for optimized usage with the IMT 2000 radio technologies. In the ongoing enhancement of IMT 2000, an all-IP conversational architecture has been selected as the base for the all-IP conversational service definition for several of the radio access technologies. This means that necessary adaptation of Internet Engineering Task Force (IETF) protocols to effectively support all-IP applications run in a mobile system radio environment is being done. Example of such work is the header compression protocol progressing in IETF ROHC Working Group (WG). All-IP multimedia services are not the evolution of the circuit switched services but represent a new category of services, mobile terminals, services capabilities, and user expectations. Any new multimedia service, which may have a similar name or functionality to a comparable standardized service, does not necessarily have to have the same look and feel from the user’s perspective of the standardized service. Voice communications (IP telephony) is one example of real-time service that would be provided as an IP multimedia application. 2 Technologies to support more efficient IP applications over mobile systemsSeveral of the IMT 2000 technologies already support end-to-end IP applications by means of the radio access bearers defined. Moreover, more advanced IP header compression has been added in order to support IP applications even more efficiently according to ongoing work in IETF ROHC WG. Currently, there is work ongoing in order to further enhance the IP application SIP signalling support by means of optimizing the transport of IP application signalling, possibly with a dedicated RAB. 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