Here are some photographs from Berlin:
All the above photographs are from The ruins of the Kaiser Wilhelm Memorial Church in Berlin, destroyed by Allied bombing in Second World War and preserved as a memorial
Latest News and Information on 4G, 5G, 6G, and other Wired & Wireless Technologies in General.
Via Licensing Corp. is looking to administer a patent pool for companies and research institutes claiming to have Intellectual Property for the emerging fast date rate cellular technology Long Term Evolution (LTE).
Testing UMTS by Dan Fox, Anritsu
Its nearly three years since I wrote an FAQ on UMTS Testing. So when I got my hands on this book the other day, I so wanted to read it. It would be a while before I manage to go through the book in detail but my initial impression is that this book looks quite good.
Since the book deals with Protocol Testing, the testing has been grouped into three categories:
There is a chapter explaining each of these. The Conformance testing is of interest to me as I have been involved directly and indirectly with this for quite some years now. The book explains the process, standards required and submission of tests to GCF/PTCRB.
For those whom testing does not hold much charm, they can gain greater understanding of the concepts by reading Part II of the book. One thing I really liked in this book is that the diagrams explain the concepts very well. Rather than copying them straight from the 3GPP specifications, they have been improved and re-done by the author. Basic things like 'Dynamic TFCI selection' and 'Layer 2 transport channel processing flow for the 12.2 kbps RMC' are explained clearly using the diagrams.
There is just the right amount of detail in the chapters for Physical Layer, Layer 2 (MAC, RLC, PDCP) and Layer 3 (RRC, NAS). Further chapters show message flow sequence charts explaining things like 'setting up of speech call' and 'location updating procedure'. I have some basic sequence diagrams for message flow in the Tutorial section but the ones in the book are comparatively more detailed.
The book mainly covers UMTS, with an introduction to HSPA. It would be worthwhile to have the next edition covering LTE in detail. The main reason being that there are lots of changes in the case of LTE. The Air Interface has changed, the channels are different. The NAS messages and entities are different. UMTS (and HSPA) use TTCN-2 for testing but LTE uses TTCN-3. UMTS does not use MIMO (MIMO available for HSPA from Release 7 onwards) but LTE would generally always use MIMO.
Overall, this seems to be a useful book and I am looking forward to reading it in detail.
Microdisplay technology maker Kopin Corp. reports it has partnered with Motorola Inc. to introduce a wireless headset with a high-definition virtual display and speech recognition for remote control of things such as smart phones and PCs.
Taunton-based Kopin (Nasdaq: KOPN) teamed up with Motorola’s Enterprise Mobility Solutions division to put a 15-inch virtual PC display together with a microphone and earpiece into the headset it calls the “Golden-i.”
According to material from Kopin, the Golden-i uses Bluetooth 2.0 to connect to the devices, as well as to Bluetooth-enabled peripherals such as a mouse, touchscreen or keyboard. Golden-i runs on the Microsoft Windows Embedded CE 6.0 R2 operating system, and once connected, users will see their PC desktop screen on the 15-inch virtual display.
To control the connected device hands-free, Kopin is incorporating the VoCon3200 software from Burlington-based Nuance Communications Inc. Golden-i also uses Nuance’s text-to-speech application to read back documents, e-mail messages, web content or any text on the display screen. According to Kopin officials, it supports up to 20 languages.
If no interface peripheral such as a Bluetooth mouse is available, Golden-i can use its built-in Hillcrest Labs 6-axis, real-time position tracker to allow control of the connected device using head gestures. The device also provides a mini-USB port, and a removable Micro SD card slot taht can support up to 32GB of memory.
The target market for Golden-i, according to Kopin, is remote workers looking to quickly connect to a PC or network for information, such as outside sales staff. It is also aimed at network support personnel, as it can support connections to multiple devices, Kopin said.Kopin, which counts the defense industry as a major customer, last December reported it had landed $3.1 million from the U.S. military for displays used in weapon sights.
Once connected to a host device, such as a PC, users see their PC desktop screen on the 15-inch virtual display and with Nuance’s VoCon3200 software they can control it using voice commands in a number of languages. Kopin claims this software provides more than 90 percent proficiency straight out of the box, and the more it is used, the better it works.
Golden-i requires no push-to-talk buttons and is ready to respond to a user’s request whether in light hibernation or during intermittent use. Golden-i also readily accepts conventional user interface from any host device touch screen, keyboard or wireless mouse and integrates Nuance text-to-speech, enabling Golden-i to read back any text displayed in a number of common languages.
Running on the Windows Embedded CE 6.0 R2 platform, Golden-i can remotely wake a PC from practically any location and, when work is finished, the PC can be placed in hibernation with a single spoken command. The headset can also remotely control up to seven other devices or networks at one time, similar to the way users control software applications on a PC desktop.
It operates much like a highly mobile server, a hub between various host devices. If a USB interface or removable memory is required, Golden-i provides a mini-USB port and a removable Micro SD card slot capable of supporting up to 32GB. Supported by Texas Instruments’ third generation OMAP dual processor platform, a single 1200 mA/hr li-ion battery should provide more than eight hours of standard use.
While the Golden-i can be used just about anywhere, it is designed for “mobile information snacking”, rather than continuous use over long periods. Initial development of the unit has focused on industrial applications, so Kopin is seeking to engage several industrial organizations in several months of in-depth field testing and evaluation. Kopin hopes to incorporate any improvements and refinements uncovered during testing into its Golden-i products, which are expected to be available in 2010.
Kopin believes Golden-i will free users from the need to carry a PC or laptop about with them. Freedom from work, though, is another matter entirely.
You can read all about the hardware and software details and features of this device here.
The figure here shows the multipath propagation for a signal. Signal goes from transmitter to the receiver through multipath that have different lengths i.e. path 1, path2 and path 3. The signal from different path arrives at the receiver at different times although it’s originated from the same source. The received symbol as shown below is longer than the duration of the original symbol.
Delay spread can cause adjacent symbols to interfere at the receiver. As a result of the multipath the delayed version of the first symbol shifts into the next symbol time and thus causes overlap between he symbols. In OFDMA this is taken care of where more time is give for each symbol to be received at the receiver by inserting a guard time.
The Doppler shift introduces another type of interference in OFDMA i.e. inter carrier interference (ICI). OFDMA divided the spectrum into narrowband subcarriers and they are tightly spaced simply because they are orthogonal. One of the requirements for orthogonality is to maintain the subcarrier spacing exactly the reciprocal of the symbol period. The figure below shows the frequency shifts thus changing the subcarrier spacing which results in the loss of orthogonality. This loss of orthogonality creates interference among the signals which is called as ICI. Since the subcarriers in OFDMA are usually very narrow hence the OFDMA system becomes very sensitive to ICI. ICI destroys the orthogonality of the OFDMA system which is overcome by the use of cyclic prefix mechanism.
Under this mechanism OFDM symbols are extended into periodical symbols i.e. redundant information is sent out to ensure that analysis can be conducted on the undistorted information and is called as cyclic extension.
It can be implemented by copying the portion of the original symbol from the end and attaching it to the front or copying it from the front and attaching it to the end. Since OFDMA has already assigned the guard time to defeat ISI, cyclic extension can be put into the guard time interval. This is called cyclic prefix. With cyclic prefix used the delayed version of the previous symbols cannot shift into the useful time of the current symbol so ISI is eliminated as well. Also the cyclic prefix provides redundant information and allows spectral analysis in the receiver to maintain the orthogonality of the subcarriers. Thus the cyclic prefix can be used to deal with both ISI and ICI.
The above concepts can be summarized in teh form of the picture below




I have added some LTE-Advanced presentations and White papers to the 3G4G website. If interested, here is the link.