RTT Technology Topics - 2001
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RTT Technology Topics
Every month we produce a technology topic that reflects current
RTT research. These are sent to an elective list of engineering,
marketing and business team leaders.
There are over 120 Topics archived on this site starting from
August 1998.
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| 2001 | Title | Synopsis |
|---|---|---|
| December | Reality gaps | In the first 5-year period (PAIN), neither handsets nor networks work well. Additionally, costs of handsets are high and end-user value is low. Why should end-users change out handsets when their old ones work perfectly well. In the next 5 years (PLEASURE), handsets easily exceed their conformance specification and the networks behave more or less as original simulations suggested. Economies of scale are realized. End-user value becomes clear. In the final 5 years (PERFECTION), the handsets and network have been developed to a point where it is technically or commercially difficult to deliver additional performance improvement. In some cases, if the air interface or network interfaces are asked to do something they were not designed to do, performance degrades. Additionally, engineers get bored and prefer to move on to new projects. |
| November | CDMA explained | How CDMA works and how processing gains are achieved. |
| October | RF and DSP 3G design optimization | The 'new' tasks taken on by the DSP now however include digital filtering, frequency selection, IQ modulation and pre-distortion (to help optimise RF PA performance). The result is that it is now much more important for DSP and RF designers to work together on performance specification |
| September | Positioning | GPS receivers have some commonality with wideband CDMA/IMT2000. The 50 bit per second data rate (almanac and ephemeric information) is modulated with a PR code unique to each satellite at 1.023 Mchips per second. Received signal energy is typically -130 dBm spread over a 2 MHz bandwidth with most of the signal energy concentrated in the centre 1 MHz. The received signal is 16 to 18 dB below the noise floor, very similar to W-CDMA. This provides some interesting correlation commonalities and has resulted in some hybrid GPS/IMT2000DS receiver designs being propositioned to the European 3G design community. However, although the signal to noise ratios are similar, the received signal levels for GPS are much lower (typically 70 nano volts versus 1 microvolt for IMT2000, ie 143 times smaller).This demands significant design attention if GPS and IMT2000DS signals are to be received simultaneously in the presence of IMT2000 transmit energy. |
| August | Packet Shaping/Traffic Shaping Protocols (Part 2) | As we move towards terabit processing speeds we move towards pico second processing (1 in 10 to the twelve). In practice we have to parallel process to meet time domain constraints. |
| July | Packet Shaping/Traffic Shaping Protocols (Part 1) | Packet routed networks promise greater bandwidth efficiency but need to deliver similar dynamic range to existing network topologies, ie to support real time rich media, packet shaping protocols have to deliver an order of magnitude improvement on existing Internet latency performance. The jury is still out as to where this is achievable. Even if it is, bandwidth efficiency will be little better than existing circuit switched networks. |
| June | Point to point to peer to peer | The peer to peer exchange of rich media implies a change in the way in which traffic is offered to a (wireless or wireline) network which in turn implies the need for new packet shaping/traffic shaping protocols and memory management methodologies. |
| May | Image, Video, Radio and Network Quality | Source coding is continuing to evolve and the related impact on radio and network bandwidth quality of service (QoS) performance expectations. |
| April | 3G Handset hardware | 'Declarative content' determines 3G handset functionality - in particular, the need for flexible, reconfigurable software and hardware platforms. |
| March | 3G Content | How to quantify content value, how to use content value as the basis of bandwidth negotiation, how to use content value as the basis for billing by quality rather than quantity |
| February | 3G Planning | Network density in a 3G cellular network is a function of the link level and system level noise floor which is a function of the property of offered traffic and offered traffic distribution. Offered traffic is a function of appliance hardware and software form factor and functionality. |
| January | 3G Costs | The variable costs implicit in delivering 'complex content'. Complex content can be defined as a mix of voice/audio streaming, image, video and application streaming. The delivery of complex content in a conversational or interactive session requires careful control of end to end latency and delay variability (often described as jitter). The degree of control needed is defined in terms of 'quality of service'. The quality of service needed will be defined by the content itself (not the subscriber).The content is 'declarative', ie it 'declares' it's bandwidth quantity and quality requirements |