89600 VSA Version Differences (802.16 OFDMA)

The IEEE Institute of Electrical and Electronics Engineers. A US-based membership organisation that includes engineers, scientists, and students in electronics and related fields. The IEEE developed the 802 series wired and wireless LAN standards. Visit the IEEE at http://www.ieee.org 802.16 OFDMA Measurement has changed over the course of many release versions. Significant changes are listed below.

Releases prior to 13.0 imply the 89601A product and those 13.0 or higher imply the 89601B product.

Graphical Zone/Burst definitions and logical subchannel allocation visual feedback within the Zone Definition editor is not available starting with release 13.0.
The "STC Space Time Coding (STC) allows the transmitter to transmit signals (information) both in time and space, meaning the information is transmitted by two antennas at two different times consecutively. Info" trace from release 7.01 has been changed to "MIMO Multiple Input, Multiple Output: A physical layer (PHY) configuration in which both transmitter and receiver use multiple antennas. Info" and now contains more complete STC/MIMO metrics.
IEEE 802.16 OFDMA uplink zone symbol offset is now specified relative to Uplink subframe start location. This is a change from the 6.10 release. Saved setup files created using 6.10 or earlier versions of the 89600 software may need to be modified. Bearing in mind:
- DownlinkRatio defines where in the frame the Uplink subframe begins, as a percentage of the frame length.
- DownlinkRatio = (Uplink subframe start time)/FrameLength

As an example, the P802.16e_ULPuscQ16.set file provided with the 6.10 release had SymbolOffset set to 26 symbols for the UL Up Link (reverse link: from cell phone to base station)-PUSC partial usage of subchannels: Some of the subchannels are allocated to the transmitter. zone. To update this setup, DownlinkRatio would be set to 0.53, and SymbolOffset would be changed to 0. The 0.53 is computed as:

52.4% = (ZoneSymbolOffset*Ns/Fs)/FrameLength

Where:

ZoneSymbolOffset: 26 symbols

Ns is the number of samples per OFDMA symbol

(FFTSize*(1+Guard Interval)): 1152 samples

Fs is the non-oversampled sample rate for the FFT Fast Fourier Transform: A mathematical operation performed on a time-domain signal to yield the individual spectral components that constitute the signal. See Spectrum. size and BW value: 11.424MHz

We round-up to 53% to ensure the Uplink subframe start occurs within the 26th symbol interval, relative to the frame start. This ensures the PRBS Pseudo-Random Binary Sequence sequence will match the existing recording (Since it uses the "Cor1/D2" compatible PRBS generator).

IEEE 802.16 OFDMA Default value for BWRatio has been updated to match the P802.16-2004/Cor1/D5 draft standard (which matches the now ratified IEEE Std 802.16e-2005 standard). This is reflected when "Standard Bandwidth" is selected. As an example, the IEEE 802.16e:10MHz preset will use a default BWRatio of 28/25, while the TTA Telecommunications Technology Association (Korea): A telecommunications standards setting body in Korea.-Phase2 (WiBro)preset still uses a default BWRatio of 8/7. Please consult the standard for a complete description of how BW and default BWRatio are coupled. In pre-D5 draft standards (and previous releases of the 89600 software) 8/7 was always the default value.
If measurements of the legacy 8/7 BWRatio are needed, the user must change the following format tab parameters:

check the "Manual Bandwidth" radio button

enter the floor-function compensated BW value (i.e. 9.996MHz for the 10MHz example, see the "Nominal Bandwidth" help topic)

and choose the 8/7 radio button of the BWRatio control

The "Gap" parameter for Uplink zone definitions has been removed and replaced with a more flexible "burst type" parameter. This allows the specification of CDMA Code Division Multiple Access: One of several digital wireless transmission methods in which signals are encoded using a specific pseudo-random sequence, or code, to define a communication channel. A receiver, knowing the code, can use it to decode the received signal in the presence of other signals in the channel. This is one of several "spread spectrum" techniques, which allows multiple users to share the same radio frequency spectrum by assigning each active user an unique code. CDMA offers improved spectral efficiency over analog transmission in that it allows for greater frequency reuse. Other characteristics of CDMA systems reduce dropped calls, increase battery life and offer more secure transmission. See also IS-95. (i.e. "Ranging") or PAPR peak to average power ratio: Peak-to-average power ratio is the ratio of the peak envelope power to the average envelope power of a signal during a given period of time. or FFB allocations within a UL-PUSC zone definition. To generate a CDMA burst which replicates a "Gap" of 1 slot, create a new burst and change its "burst type" to CDMA, then change the dimensions of the burst to occupy all subchannels over an entire slot. This new handling allows for defining CDMA or PAPR or FFB allocations within the zone that occupy only a subset of subchannels, and are located anywhere within the zone. No measurements are made of the PAPR or FFB regions, but they are accounted for in the UL-PUSC subchannel mapping.

Zone Boosting compensation for DL Down Link (forward link: from base station to cell phone)-PUSC zones is now performed automatically. If a DL-PUSC signal does not use all subchannel groups (one or more of the Subchannel Group Bitmask bits are turned off), and Zone Boosting is not used by the waveform, then a mis-scaled constellation and high EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format. will result. This situation can still be measured by turning ON pilot amplitude tracking (on the advanced tab).