TGac Channel Model Addendum Supporting Material

May 2009 doc.: IEEE 802.11-09/0569r0

Submission page 1 Greg Breit, Qualcomm

IEEE P802.11

Wireless LANs

TGac Channel Model Addendum Supporting Material

May, 2009

Phillipe Chambelin, philippe.chambelin@thomson.net

John Benko, john.benko@orange-ftgroup.com

Laurent Cariou, laurent.cariou@orange-ftgroup.com

VK Jones, vkjones@qualcomm.com

Allert Van Zelst, allert@qualcomm.com

May 2009 doc.: IEEE 802.11-09/0569r0

Submission page 2 Greg Breit, Qualcomm

This document provides background material for the addendum to TGn channel model

document (IEEE802.11-09/0308r3) to be used for the Very High Throughput Task Group

May 2009 doc.: IEEE 802.11-09/0569r0

Submission page 3 Greg Breit, Qualcomm

Maintains supporting material removed from r3 of that doc.

support for 40 MHz channelization and 4 antennas. The TGac task group is targeting > 1

Gbps MAC SAP throughput using one or more of the following technologies:

 Higher order MIMO (> 4x4)

 Higher Bandwidth (> 40 MHz)

 Multi-User MIMO with > 4 AP antennas

 OFDMA

In this document we propose some simple modifications to TGn channel models to enable

their use for TGac with accompanying supporting simulations and measurement data..

May 2009 doc.: IEEE 802.11-09/0569r0

Submission page 4 Greg Breit, Qualcomm

Expansion Factor

expansion factor k (new sampling rate = k*100MHz), a sequence of k-1 new taps,

the sequence shall occur 10/k ns after the TGn-defined tap. The power assigned to

powers immediately before and after the new tap, in proportion to its position in time

Figure 1 illustrates this procedure for the example of k=4 (new channel sampling rate =

400MHz), for a hypothetical pair of TGn-defined taps spaced 20ns apart. The TGn taps are

denoted by the thick grey arrows, and the new interpolated taps are denoted by the thin black

May 2009 doc.: IEEE 802.11-09/0569r0

Submission page 5 Greg Breit, Qualcomm

To validate the proposed interpolation scheme, we assess the difference between the existing

TGn channel and the interpolated TGac channel in terms of delay spread, Ricean K factor,

and link performance.

The proposed scheme was applied to interpolate TGn Models B-F from 20MHz to 80MHz

bandwidth. The RMS delay spreads (in ns) of the 20MHz non-interpolated (TGn) and 80

agreement with the original non-interpolated model.

Table 2: RMS delay spread (ns) of TGn and interpolated TGac channel models

Table 3 shows the median Ricean K factor calculated from 1600 random instances of each

LOS channel model for both the original TGn channel and the 80MHz interpolated TGac

channels. The frequency domain channel was converted to time domain by IFFT and the K

instance. These results demonstrate that channel bandwidth expansion by tap interpolation

does not bias the K factor of the resulting modeled channels.