Shu (Marloon) Wang

A Signal Processing Perspective The statistic properties of the PAPR of multi-carrier signals can be described by CCDF (Complementary Cumulative Distribution Function). If we assume the frequency-domain symbol is complex Gaussian distributed. When the number of subcarriers, L , become large, the instantaneous power of each multi-carrier signal chip can be modeled by a Chi-distributed signal with two degree of freedom. CCDF( γ ) = Pr( PAPR > γ ) = 1- Pr( PAPR <= γ ) = 1 – [ Pr( p <= γ ) ] L >~ 1 – ( 1 – e -γ ) L   Figure 1.  A statistic modeling of PAPR A Coding Perspective Given a code of length n , coding rate R, what is the achievable region of triplets ( R , d , PMEPR) ?  What is the relationship between PMEPR and the minimum Euclid distance (mED) d * ? All these questions belong to a Sphere Packing Problem. Given a codeset of q-ary code c with length n , what is the relationship between the size of the codeset and minimum Hamming distance (mHD) D ? This is a Sp

[Contribution to 3GPP2 Next Generation Technologies Ad Hoc Group (NTAH) 2007] With the upcoming deployment of wideband wireless network with throughput greater than 100Mbps over high frequency bands such as 5-GHz band and the adopting of multicarrier modulations, more and more challenges are brought to system and hardware design. OFDM, frequently referred as multi-carrier modulation, is becoming the de facto standard for next-generation wideband wireless networks. However, one of the critical issues of OFDM as well as other multicarrier modulation scheme is its high peak-to-average power ratio (PAPR), which usually requires large backoff and highly efficient high power amplifier (HPA), large dynamic range analog-to-digital converter (ADC), high linearity up-converter, etc. These requirements lead to expensive hardware systems that are difficult to design. Hence it becomes more and more important to alleviate the burden of hardware design with employing advanced PAPR reduction technol