**2. The noise impact of camera and Touch Panel (TP) modules on product performance**

#### **2.1 Performance testing for Wireless Wide Area Network (WWAN) devices**

There are two different purposes for the OTA (Over-The-Air) testing[3] on mobile stations. The first testing is for the carrier's cell site coverage which is relative with loss plan and link budget of the cell site. For example, the sensitivity measurement of the W-CDMA receiver is performed by the base-station simulator to determine the receiving sensitivity of EUT (Equipment Under Test) by reporting the minimum forward-link power which resulting in a bit-error-rate (BER) of 1.2% or less at the data rate of 12.2 kbps with a minimum of 20,000 bits. The second tresting is the throughput for supporting all kind of the applications for cloud computing. The minimum throughput required will depend on application. For example, the minimum throughput we need to link YOU TUBE for HD video is about 1Mbps at least. Therefore, the mobile station (Smart Phone, Tablet PC, Note book PC, etc.) is required the OTA performance testing on TRP, TIS and De-Sense.

#### **2.1.1 Total Radiated Power (TRP)**

TRP measurement is to evaluate the transmitting RF power performance of mobile device by summing the effective isotropic radiated power (EIRP) of complete Theta- and Phi-cut as shown in Figure 2. The procedure is first to measure the radiated power at each Phi degree interval for 360 degree rotation ( if interval is 30 degree then it need 12 measurement), and then for the Theta axial. Finishing the 180 degree rotation along Theta axial, the TRP is obtained with following formula.

$$TRP \cong \frac{\pi}{2NM} \sum\_{i=1}^{N-1} \sum\_{j=0}^{M-1} \left[ EIRP\_{\phi}(\theta\_i, \phi\_j) + EIRP\_{\phi}(\theta\_i, \phi\_j) \right] \text{sim}(\theta\_i) \tag{1}$$

notebook computer to effectively suppress noise source-antenna coupling and improve the

receiving sensitivity of wireless communication system.

Fig. 1. S/N ratio decreases due to digital components for multi-functions.

required the OTA performance testing on TRP, TIS and De-Sense.

**2.1.1 Total Radiated Power (TRP)** 

obtained with following formula.

**performance** 

**2. The noise impact of camera and Touch Panel (TP) modules on product** 

There are two different purposes for the OTA (Over-The-Air) testing[3] on mobile stations. The first testing is for the carrier's cell site coverage which is relative with loss plan and link budget of the cell site. For example, the sensitivity measurement of the W-CDMA receiver is performed by the base-station simulator to determine the receiving sensitivity of EUT (Equipment Under Test) by reporting the minimum forward-link power which resulting in a bit-error-rate (BER) of 1.2% or less at the data rate of 12.2 kbps with a minimum of 20,000 bits. The second tresting is the throughput for supporting all kind of the applications for cloud computing. The minimum throughput required will depend on application. For example, the minimum throughput we need to link YOU TUBE for HD video is about 1Mbps at least. Therefore, the mobile station (Smart Phone, Tablet PC, Note book PC, etc.) is

TRP measurement is to evaluate the transmitting RF power performance of mobile device by summing the effective isotropic radiated power (EIRP) of complete Theta- and Phi-cut as shown in Figure 2. The procedure is first to measure the radiated power at each Phi degree interval for 360 degree rotation ( if interval is 30 degree then it need 12 measurement), and then for the Theta axial. Finishing the 180 degree rotation along Theta axial, the TRP is

(1)

**2.1 Performance testing for Wireless Wide Area Network (WWAN) devices** 

Fig. 2. Total Radiated Power measurement.

For the ideal case, the TRP should be equal to the conducted power (Watts) times mismatching Loss (%) and antenna efficiency as shown in following relationship and illustration. But the antenna efficiency measurement can actually with error resulting from coaxial cable connection as illustrated in Figure 3. When the coaxial cable is connected to the SMA connector, the surface on it could cause measurement error of the antenna efficiency.

$$TRP = \frac{1}{4\pi} \int\_{\phi \to \phi}^{\pi} \int\_{\phi \to \phi}^{2\pi} (EilRP\_o(\theta, \phi) + EilRP\_\phi(\theta, \phi)) \sin(\theta) d\theta d\phi$$

$$TRP = P\_\Lambda \cdot L\_w \cdot eff$$

Transmit Power = Pc (Conducted Power) + Antenna Gain (in dB)

Fig. 3. Illustration of Antenna TRP.

#### **2.1.2 Total Isotropic Sensitivity (TIS)**

The measurement setup for TIS testing is the same as shown in Figure 2, except with the different calculation. It is analogous to calculate the total resistance form the parallel resistor network. The Effective Isotropic Sensitivity (EIS) is illustrated in Figure 4 and calculated with following formula.

$$TIS \triangleq \frac{2NM}{\pi \sum\_{i=1}^{N} \sum\_{j=0}^{M-1} \left[ \frac{1}{EIS\_{\vartheta}(\boldsymbol{\theta}\_{i}, \boldsymbol{\phi}\_{j})} + \frac{1}{EIS\_{\varphi}(\boldsymbol{\theta}\_{i}, \boldsymbol{\phi}\_{j})} \right] \sin(\boldsymbol{\theta}\_{i})} \tag{3}$$

$$G\_{s, t \mid t \mid t} \left( \theta, \phi \right) = \frac{P\_{\tilde{s}}}{E \| S\_x \left( \theta, \phi \right) \|} \tag{4}$$

$$\overline{TS} = \frac{4\pi}{\oint \frac{1}{EIS\_{\phi}(O,\phi)} + \frac{1}{EIS\_{\phi}(O,\phi)}} \Big|\_{} \sin(\theta) \mathbf{x} d\theta d\phi \tag{5}$$

For the ideal case, TIS should be equal to conductive sensitivity divided by mismatching loss and antenna efficiency as shown in following relationship and illustration. Not only the surface current on coaxial cable would cause the antenna efficiency measurement error, but also the platform noise interference investigated here would de-sense the receiver.

EIS: Effective Isotropic Sensitivity = Received EIRP – Antenna Gain (in dB) TIS: Total Isotropic Sensitivity (3D Measurement)

Fig. 4. Illustration of Antenna TIS.

180 Wireless Communications and Networks – Recent Advances

Transmit Power = Pc (Conducted Power) + Antenna Gain (in dB)

The measurement setup for TIS testing is the same as shown in Figure 2, except with the different calculation. It is analogous to calculate the total resistance form the parallel resistor network. The Effective Isotropic Sensitivity (EIS) is illustrated in Figure 4 and calculated

(4)

For the ideal case, TIS should be equal to conductive sensitivity divided by mismatching loss and antenna efficiency as shown in following relationship and illustration. Not only the surface current on coaxial cable would cause the antenna efficiency measurement error, but

also the platform noise interference investigated here would de-sense the receiver.

(2)

(3)

(5)

Fig. 3. Illustration of Antenna TRP.

with following formula.

**2.1.2 Total Isotropic Sensitivity (TIS)** 

The relationship between receiver performance and platform noise is described by receiver bit error rate and energy per bit (Eb) /Noise(N0) as shown in Figure 5. For example, the WCDMA receiver sensitivity with QPSK modulation can be determined as following:

Bit Error Rate (BER): 1.2% BER for QPSK demodulation receiver require that Eb/N0 = 7.5dB

where Eb: measured at base-band output ( I/Q output) for each bit.

 No: total noise power form RF front end to base-band, include LNA NF, ADC, quantize noise, PLL phase Noise,…with Gaussian system noise representation.

Fig. 5. Receiver Bit Error Rate vs. Energy per bit (Eb) /Noise(N0).

The BER is measured in time domain after demodulation of receiver. For WCDMA system, it needs 20k bits / 12.2Kbps = 1.64 second at each receiving channel. From communication demodulation theory, N0 is described as Gaussian noise, and it is the sum of the receiver noise (related to implementation loss) and system noise as illustrated in the following figures.

Fig. 6. Illustration of system noise effect.

Based on TIS requirement for WWAN or WLAN throughput, the noise limit of the wireless system should be set to meet the regulatory specification. Figure 7 shows the sensitivity degradation due to self-interference for GSM 1800 and WCDMA systems. The example for WCDMA system is following:

Noise Limit: TIS (dBm) + Antenna Gain (dB) – Eb/N0(dB) + Processing Gain (demodulation dependence) – System Losses (6dB) (depending on chip set, LNA NF, PLL phase nosie, ADC…..), Processing Gain (dB)=10 Log( Chip rate/Data Rate) = 10log (3840K/12.2K)= 25dB

WCDMA Noise Limit : Gaussian Probability Density Function Noise Power-103dBm + (- 5dB) -7.5dB +25dB – 6dB = 96.5dBm

Based on TIS requirement for WWAN or WLAN throughput, the noise limit of the wireless system should be set to meet the regulatory specification. Figure 7 shows the sensitivity degradation due to self-interference for GSM 1800 and WCDMA systems. The example for

Noise Limit: TIS (dBm) + Antenna Gain (dB) – Eb/N0(dB) + Processing Gain (demodulation dependence) – System Losses (6dB) (depending on chip set, LNA NF, PLL phase nosie, ADC…..), Processing Gain (dB)=10 Log( Chip rate/Data Rate) = 10log (3840K/12.2K)= 25dB WCDMA Noise Limit : Gaussian Probability Density Function Noise Power-103dBm + (-

Fig. 6. Illustration of system noise effect.

WCDMA system is following:

5dB) -7.5dB +25dB – 6dB = 96.5dBm

Fig. 7. Sensitivity degradation examples for GSM 1800 and WCDMA systems.

However, since there are more than one thousand Channels for GSM and WCDMA systems, we can't test all receiving channels for those WWAN devices. The alternative way for testing those intermediate channels is to measure the relative sensitivity as following steps and illustration as shown in Figure 8:


Fig. 8. Alternative way for testing relative sensitivity of intermediate channels.
