Oct 2005 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ICI Analysis] Date Submitted: [4 Oct 2005] Source: [Rick Roberts] Company [Harris Corporation] Address [Melbourne, Florida] Voice:[321-729-3018], FAX: [], E-Mail:[rrober14@harris.com] Re: [] Abstract: [ICI Analysis] Purpose: [] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Rick Roberts, Harris Corp

TX Filtering Induced InterChip Interference (ICI) Analysis Oct 2005 TX Filtering Induced InterChip Interference (ICI) Analysis Rick Roberts, Harris Corp

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> Oct 2005 Block Diagram Code 1 Cross Correlator 50% Excess BW RRC or Guassian 50% Excess BW RRC or Guassian Auto Corr Code 1 BPSK MOD BPSK DEMOD Low Pass Low Pass Cross Correlator Cross Corr 4.5 GHz LO Code 2 Rick Roberts, Harris Corp <author>, <company>

For this analysis I’ve used codes that have predictable properties. Oct 2005 Summary InterChip Interference (ICI) at the transmitter output occurs as the chipping rate approaches the Nyquist rate. The ICI significantly increases as the chipping rate is increased beyond the Nyquist rate. This ICI impacts the transmitted code word, namely it degrades the cross correlation between previously nearly orthogonal code words and it increases the TX peak output power. The approach presented in document 15-05-0556-00-004a is hard to evaluate because the codes are random (due to the scrambler cover code), meaning they don’t have predictable cross correlation properties except over long average. This may be problematic if we are depending upon the code to support SOP via some measure of CDMA. For this analysis I’ve used codes that have predictable properties. Rick Roberts, Harris Corp

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> Oct 2005 Code Words* Source 1: -+--+--+-0-0--+++-+++--- Source 2: --+0+++--+-++-+0+---+--- * Extracted from Document 802.15-03/153r6, 2-BOK codes for PNC1 and PNC2 (slide 10) Rick Roberts, Harris Corp <author>, <company>

Oct 2005 Root Raised Cosine Gaussian -3 dB BW is 500 MHz Rick Roberts, Harris Corp

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> Oct 2005 Chip Eye Patterns vs. Chipping Rate for Fixed 500 MHz BW RRC Gaussian 625 Mcps 500 Mcps 250 Mcps 100 Mcps Rick Roberts, Harris Corp <author>, <company>

Oct 2005 Rick Roberts, Harris Corp

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> Oct 2005 Note: while actual results will vary with other nearly orthogonal codewords, they will show similar degradation Rick Roberts, Harris Corp <author>, <company>

Oct 2005 Conclusion It is better that the chipping rate does not exceed the Nyquist rate as determined by the pulse forming network (chipping rate filter). To do so increases the TX peak power and also starts to impact the code properties (if any). Rick Roberts, Harris Corp