How to Broadcast Multimedia Contents? VI Open-Loop MIMO for Broadcast Multicast Services

What Is The Next for Mobile System Design? I A Single-Cell Model Perspective on Downlinks
[How to Broadcast Multimedia Contents? I Introduction]
[How to Broadcast Multimedia Contents? II Lessons from The Channel]
[How to Broadcast Multimedia Contents? IV Hierarchical Modulation]
[How to Broadcast Multimedia Contents? V Overloaded Transmission and IC]
[How to Broadcast Multimedia Contents? VII Network Layer or Steam Layer Design]

One most well-known space-time block coding (STBC) design is Alamouti code, which is the simplest open-loop orthogonal STBC. Alamouti code was designed for a two-transmit antenna system. It is a rate-1 code. It is the first open-loop encoding method with full diversity. Though orthogonal STBC has the advantages of relatively easy receiver design and full diversity, it is known that full-rate STBC don’t exist for more than 2 transmit antenna. From previous discussion, if two orthogobal STBCs are superimposed together and each of them experiences different channel fading, there would be multi-layer diversity in addition to potential superposition precoding gain. This means one STBC signal layer is in a bad channel condition, the other STBC signal layer may not. Therefore, the transmission of more than one layers may have higher achievable spectral efficiency.


Figure 1. A Quasi-Orthogonal Space Time Block Coding Example


One widely discussed example of quasi-orthogonal STBC is shown in Figure 1. From a receiver perspective, this quasi-orthogonal STBC obviously has a larger signal constellation size. In general, larger the signal constellation size is, high the spectral efficiency is achievable. Besides this, it may have so-called multilayer diversity when it experiences channel fading since each orthogonal STBC signal experiences different fading. However, there is no free lunch. The demodulation complexity may increase exponentially with the number of superimposed STBC layers.

Comments

Post a Comment

Popular posts from this blog

Hack Apple TV for Watching Chinese TVs and Videos

Image
[ Hack Patriot Box Office for Watching Chinese Videos and TVs ] Figure 1.   Apple TV Apple TV (ATV) is a  multi-function set-top box  designed by Apple Inc. originally as a  networked media player  for streaming multimedia contents to a television or an external monitor.  Now, it seemingly evolves into a iPod Touch without a touch screen but with a relatively inexpensive MSRP price tag of $99.  (Indeed, if you have an old generation iPod Touch, you may think about mirroring or airplay it onto a television instead.)  On March 7, 2012, Apple Inc. released a  3rd generation ATV (ATV3)   that includes a 32 nm ARM Cortex-A9 Apple A5 SoC (the same process as used in a 5th generation iPod Touch, a new iPad 2 and an iPad Mini) and 512MB mobile DDR2 memory (the same amount of memory as used in an iPhone 4).  An ATV3 has a buit-in 6 W power supply with no cooling fan necessary.  Unfortunately, until now, there is no public released jailbreak available for an ATV3, so modified software or
Read more

Hack Patriot Box Office for Watching Chinese Videos and TVs

As requested by friends, this blog is dedicated to explain a simple way for watching Chinese TV programs and movies on a television or monitor for free using a special media player instead of a computer.  Compared with many well-known approaches watching Chinese TVs on a computer, this one seems much more operation-friendly as well as eco-friendly.  It is attractive for many Chinese families who may not always be technical savvy.  In addition, as I know, the operation cost or power consumption of this kind of MIPS-based media players is relatively low.  Its total power consumption usually is no more than 15 watts.  Meanwhile, a typical power consumption of a PC CPU, even some mobile or laptop CPUs,  itself is known to be between 50 watts and 100 watts.  Even a power efficient Intel Atom CPU usually is inside a range between 5 and 20 watts, as I remember.  Nowadays a typical home desktop demands a power supply of no less than 250 watts, not to mention that a powerful game desktop or wo
Read more

How to Broadcast Multimedia Contents? II Lessons from The Channel

Image
What Is The Next for Mobile System Design? I A Single-Cell Model Perspective on Downlinks [How to Broadcast Multimedia Contents? I Introduction] [How to Broadcast Multimedia Contents? IV Hierarchical Modulation] [How to Broadcast Multimedia Contents? V Overloaded Transmission and IC] [How to Broadcast Multimedia Contents? VI Open-Loop MIMO for BCMCS] [How to Broadcast Multimedia Contents? VII Network Layer or Stream Layer Design] COST 231 model, which was developed by European COST Action 231, and its variations are the most popular radio propagation model adopted in various standardization bodies, such as 3GPP, 3GPP2 and IEEE. Its modifications include COST 231-Hata Model and COST 231-Walfisch-Ikegami Model . The mathematical formulation of the COST 231-Hata model path loss in dB is PL = 46.3 + 33.9 logf - 13.82log h BS - a( h MS ) + [ 44.9-6.55logh BS ] log d + C which features a carrier frequency f between 800MHz and 2GHz, an above-neighborhood base station antenna w
Read more