**4. Effect of UWB Interference on the UMTS and CDMA-450 macrocell downlink performance**

To account for the UWB interference, an extra source of interference is added linearly to the UMTS and the CDMA-450 intra-system interference. The interference power is calculated by assuming the UWB source to be at different distances from the UMTS receiver (the mobile station). Therefore, the interference power generated by a UWB device, IUWB, is given by (in dBm):

$$I\_{\rm LINB} = P\_{\rm LINB} - L\_{\rm LINB}(d) + G\_{\rm LINTS} \tag{9}$$

UWB Coexistence with 3G and 4G Cellular Systems 321

(14)

(15)

(16)

**UWB**

In the frequency band used by CDMA-450, the UWB signal propagation loss in dB is

<sup>10</sup> ( ) 25.7 20log ( ) 4 *UWB L d* ≈+ − *d*

*CDMA CDMA CDMA o CDMA UWB*

 = +

*CDMA*

*CDMA UWB*

*I I* = +

Fig. 1 represents the scenario of the studied WiMAX system. It shall be mentioned that the receiver is an indoor portable WiMAX. The UWB transmitter is also indoor within a distance

**WiMAX signal**

Let us study the case of 3.5 GHz WiMAX assuming that the WiMAX transmission power is 40 dBm/sector. Fig. 2 shows the WiMAX downlink modulation modes, as a function of distance between the WiMAX transmitter and receiver, for three different UWB power densities. It can be noticed that, without UWB interference, the WiMAX will have a range of 1481 m for the

,

*n*

**5. Results for a WiMAX system and a single UWB interferer** 

of 0.5 to 5 m from the WiMAX receiver.

**WiMAX interference** 

**Figure 1.** WiMAX studied scenario.

*<sup>I</sup> <sup>C</sup>*

*R I R II*

• RCDMA,o is the CDMA-450 macrocell initial range without the UWB interference. • RCDMA is the CDMA-450 macrocell range with the existence of the UWB interference. The normalized capacity of the CDMA-450 system Cn is given by (Ahmed et. al., 2008):

The normalized range is now given by (Ahmed et. al., 2008):

σ

1/

γ

calculated as:

where:

Where:


As the UWB devices are typically low power and short range devices the line-of-sight pathloss model is often most appropriate. Then the UWB signal propagation loss in dB is calculated as:

$$L\_{\rm LWB}(d) = \Im \theta.03 + \Im 0 \log\_{10}(d) - 4\sigma \tag{10}$$

The effect of the UWB interference is to reduce the UMTS macrocell range or/and the macrocell capacity.

The normalized range is given as (Ahmed et. al., 2008):

$$\frac{R\_{\rm LMTS}}{R\_{\rm LMTS,o}} = \left(\frac{I\_{\rm LMTS}}{I\_{\rm LMTS} + I\_{\rm LINB}}\right)^{1/\gamma} \tag{11}$$

The normalized capacity Cn is given as (Ahmed et. al., 2008):

$$\mathbf{C}\_{n} = \left(\frac{I\_{\rm LIMTS}}{I\_{\rm LIMTS} + I\_{\rm LIWN}}\right) \tag{12}$$

The interference power generated by a UWB device that affects the CDMA-450 receiver, IUWB, is given by (in dBm):

$$I\_{\rm LINB} = P\_{\rm LINB} - L\_{\rm LINB} \text{(d)} + G\_{\rm CDMA} \tag{13}$$

where:


In the frequency band used by CDMA-450, the UWB signal propagation loss in dB is calculated as:

$$L\_{\rm LWB}(d) = 25.7 + 20\log\_{10}(d) - 4\sigma \tag{14}$$

The normalized range is now given by (Ahmed et. al., 2008):

$$\frac{R\_{\text{CDMA}}}{R\_{\text{CDMA},o}} = \left(\frac{I\_{\text{CDMA}}}{I\_{\text{CDMA}} + I\_{\text{IDWB}}}\right)^{1/\gamma} \tag{15}$$

where:

320 Ultra Wideband – Current Status and Future Trends

**downlink performance** 

dBm):

Where:

calculated as:

macrocell capacity.

IUWB, is given by (in dBm):

where:

**4. Effect of UWB Interference on the UMTS and CDMA-450 macrocell** 

To account for the UWB interference, an extra source of interference is added linearly to the UMTS and the CDMA-450 intra-system interference. The interference power is calculated by assuming the UWB source to be at different distances from the UMTS receiver (the mobile station). Therefore, the interference power generated by a UWB device, IUWB, is given by (in

() *UWB UWB UWB UMTS I P L dG* =− + (9)

• LUWB(d) is the path-loss between the UWB device and the UMTS receiver which varies

As the UWB devices are typically low power and short range devices the line-of-sight pathloss model is often most appropriate. Then the UWB signal propagation loss in dB is

<sup>10</sup> ( ) 39.03 20log ( ) 4 *UWB L d* ≈+ − *d*

,

*n*

*<sup>I</sup> <sup>C</sup>*

*R I R II*

*UMTS UMTS UMTS o UMTS UWB*

 <sup>=</sup> +

*UMTS*

*UMTS UWB*

*I I* = +

The interference power generated by a UWB device that affects the CDMA-450 receiver,

() *UWB UWB UWB CDMA I P L dG* =− + (13)

• LUWB(d) is the path-loss between the UWB device and the CDMA-450 receiver which

The effect of the UWB interference is to reduce the UMTS macrocell range or/and the

σ

1/

γ

(10)

(11)

(12)

• PUWB is the mean UWB EIRP in dBm in the UMTS band.

with the separation distance, d in m, and

The normalized range is given as (Ahmed et. al., 2008):

The normalized capacity Cn is given as (Ahmed et. al., 2008):

• PUWB is the UWB EIRP in dBm in the CDMA-450 band.

varies with the separation distance, d in m, and

• GCDMA is the CDMA-450 antenna gain .

• GUMTS is the UMTS antenna gain.


The normalized capacity of the CDMA-450 system Cn is given by (Ahmed et. al., 2008):

$$C\_n = \left(\frac{I\_{\text{CDMA}}}{I\_{\text{CDMA}} + I\_{\text{IDWB}}}\right) \tag{16}$$

## **5. Results for a WiMAX system and a single UWB interferer**

Fig. 1 represents the scenario of the studied WiMAX system. It shall be mentioned that the receiver is an indoor portable WiMAX. The UWB transmitter is also indoor within a distance of 0.5 to 5 m from the WiMAX receiver.

Let us study the case of 3.5 GHz WiMAX assuming that the WiMAX transmission power is 40 dBm/sector. Fig. 2 shows the WiMAX downlink modulation modes, as a function of distance between the WiMAX transmitter and receiver, for three different UWB power densities. It can be noticed that, without UWB interference, the WiMAX will have a range of 1481 m for the second modulation scheme. With a UWB power density of -88.5 dBm/MHz the range will be reduced by 2% and with a UWB power density of -41.3 dBm/MHz (recommended by FCC), the range will be only 213 m. Such a reduction drastically degrades the WiMAX performance.

UWB Coexistence with 3G and 4G Cellular Systems 323

 **PUWB/MHz = -41.3 dBm PUWB/MHz = -88.5 dBm**

 **PUWB/MHz = -41.3 dBm PUWB/MHz = -91.5 dBm**

 **No UWB**

 **No UWB**

**Figure 3.** 3.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the UWB transmitter and the WiMAX receiver assuming a WiMAX transmitted power of 40 dBm/sector and that the WiMAX signal and interference are received through an open window.

200 400 600 800 1000 1200 1400 1600 1800 2000

 **Distance Between WiMAX Tx. and WiMAX Rx. (m)**

 **WiMAX Modulation modes**

 **WiMAX Modulation modes**

**Figure 4.** 3.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the UWB transmitter and the WiMAX receiver assuming a WiMAX transmitted power of 40

200 400 600 800 1000 1200 1400

 **Distance Between WiMAX Tx. and WiMAX Rx. (m)**

dBm/sector.

0

 **Modulation mode**

 **Modulation mode**

**Figure 2.** 3.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the UWB transmitter and the WiMAX receiver assuming a WiMAX transmitted power of 40 dBm/sector.

Let us consider now the case when the WiMAX signal and also the interference are received through an open window. Fig. 3 shows the WiMAX downlink modulation modes, again as a function of distance between the WiMAX transmitter and receiver, for three different UWB power densities. As can be seen, without UWB interference, the WiMAX will have a range of 1930 m for the second modulation scheme. With a UWB power density of -88.5 dBm/MHz the range will be reduced by 2%. And for a UWB power density of -41.3 dBm/MHz (recommended by FCC), the range will be 310 m. Again the WiMAX range performance is drastically degraded.

Let us now study the case presented in Fig. 2 but assuming this time that the maximum allowed WiMAX reduction range is 1%. Fig. 4 shows the WiMAX downlink modulation modes as a function of distance between the WiMAX transmitter and receiver for three different UWB power densities. It is clearly seen that, without UWB interference, the WiMAX will have a range of 1481 m for the second modulation scheme. The range will be reduced by 1% when the interfering UWB power density is -91.5 dBm/MHz.

Let us consider now the case when the WiMAX system operates in the 2.5 GHz band. Fig. 5 shows the WiMAX downlink modulation modes as a function of distance between the

dBm/sector.

drastically degraded.

0

1

2

3

4

5

 **Modulation mode**

6

7

8

9

10

second modulation scheme. With a UWB power density of -88.5 dBm/MHz the range will be reduced by 2% and with a UWB power density of -41.3 dBm/MHz (recommended by FCC), the range will be only 213 m. Such a reduction drastically degrades the WiMAX performance.

 **WiMAX Modulation modes**

 **PUWB/MHz = -41.3 dBm PUWB/MHz = -88.5 dBm**

 **No UWB**

**Figure 2.** 3.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the UWB transmitter and the WiMAX receiver assuming a WiMAX transmitted power of 40

200 400 600 800 1000 1200 1400

 **Distance Between WiMAX Tx. and WiMAX Rx. (m)**

Let us consider now the case when the WiMAX signal and also the interference are received through an open window. Fig. 3 shows the WiMAX downlink modulation modes, again as a function of distance between the WiMAX transmitter and receiver, for three different UWB power densities. As can be seen, without UWB interference, the WiMAX will have a range of 1930 m for the second modulation scheme. With a UWB power density of -88.5 dBm/MHz the range will be reduced by 2%. And for a UWB power density of -41.3 dBm/MHz (recommended by FCC), the range will be 310 m. Again the WiMAX range performance is

Let us now study the case presented in Fig. 2 but assuming this time that the maximum allowed WiMAX reduction range is 1%. Fig. 4 shows the WiMAX downlink modulation modes as a function of distance between the WiMAX transmitter and receiver for three different UWB power densities. It is clearly seen that, without UWB interference, the WiMAX will have a range of 1481 m for the second modulation scheme. The range will be

Let us consider now the case when the WiMAX system operates in the 2.5 GHz band. Fig. 5 shows the WiMAX downlink modulation modes as a function of distance between the

reduced by 1% when the interfering UWB power density is -91.5 dBm/MHz.

**Figure 3.** 3.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the UWB transmitter and the WiMAX receiver assuming a WiMAX transmitted power of 40 dBm/sector and that the WiMAX signal and interference are received through an open window.

**Figure 4.** 3.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the UWB transmitter and the WiMAX receiver assuming a WiMAX transmitted power of 40 dBm/sector.

UWB Coexistence with 3G and 4G Cellular Systems 325

 **PUWB/MHz = -41.3 dBm PUWB/MHz = -97.5 dBm**

 **No UWB**

**Figure 6.** 3.5 GHz WiMAX downlink modulation modes versus distance between the WiMAX

the WiMAX receiver and assuming a WiMAX transmitted power of 40 dBm/sector.

reduction, unless Detect and Avoid (DAA) techniques are implemented.

subcarriers with a 40 dB notch filter.

0

1

2

3

4

5

 **Modulation mode**

6

7

8

9

10

by 1%.

transmitter and receiver, for different UWB power densities from 4 UWB transmitters at 1 m distance to

200 400 600 800 1000 1200 1400

 **WiMAX Modulation modes**

 **Distance Between WiMAX Tx. and WiMAX Rx. (m)**

A band rejection up to 56 dB is needed for the DS-CDMA UWB system, while for the MB-OFDM UWB system a 51 dB band rejection is needed and can be obtained by nulling 16

We study now the same scenario but for the 2.5 GHz WiMAX. Fig. 7 shows the WiMAX downlink modulation modes as a function of the distance between the WiMAX transmitter and receiver for three different UWB power densities. It can be noticed that for the second modulation scheme without UWB interference, the WiMAX will have a range of 1817 m. At a UWB power density of -100.7 dBm/MHz, WiMAX range will be reduced

In summary, from the results presented in Figures 2, 3, 4 and 5 it can be concluded that the power density of -41.3 dBm/MHz recommended by FCC, implies a very high range

Fig. 8 represents the DAA requirement for Multiband OFDM UWB (MB-OFDM UWB) system and the Direct Sequence CDMA system (DS-CDMA UWB), with activity factors

(fraction of the time they work at the 3.5 GHz band) of 32% and 100% respectively.

**Figure 5.** 2.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the UWB transmitter and the WiMAX receiver assuming a WiMAX transmitted power of 40 dBm/sector.

WiMAX transmitter and receiver for three different UWB power densities. Notice that, without UWB interference, the WiMAX will have a range of 1817 m for the second modulation scheme. With a UWB power density of -94.7 dBm/MHz the range will be reduced by 1%. For a UWB power density of -51.3 dBm/MHz (recommended by FCC), the range will be 378 m and such a reduction represents a drastic degradation of the WiMAX performance. In this case an UWB with a power density of -91.5 dBm/MHz will reduce the WiMAX range by 2%.

#### **6. Results for a WiMAX system and multi UWB interferers**

We will consider now the case of multi-UWB transmitters, assuming the case that 4 UWB are located at a distance of 1m from the WiMAX receiver. Fig. 6 shows the WiMAX downlink modulation modes as a function of the distance between the WiMAX transmitter and receiver (WiMAX link length) for three different UWB power densities. It can be noticed that, without UWB interference, the WiMAX will have a range of 1481 m for the second modulation scheme. The range will be reduced by 1% when the UWB power density is higher than -97.5 dBm/MHz. In this case, an UWB power density of -94 dBm/MHz will reduce the WiMAX range by 2%.

dBm/sector.

WiMAX range by 2%.

0

1

2

3

4

5

 **Modulation mode**

6

7

8

9

10

reduce the WiMAX range by 2%.

**Figure 5.** 2.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the UWB transmitter and the WiMAX receiver assuming a WiMAX transmitted power of 40

200 400 600 800 1000 1200 1400 1600 1800 2000

 **Distance Between WiMAX Tx. and WiMAX Rx. (m)**

 **WiMAX Modulation modes**

 **PUWB/MHz = -51.3 dBm PUWB/MHz = -94.7 dBm**

 **No UWB**

WiMAX transmitter and receiver for three different UWB power densities. Notice that, without UWB interference, the WiMAX will have a range of 1817 m for the second modulation scheme. With a UWB power density of -94.7 dBm/MHz the range will be reduced by 1%. For a UWB power density of -51.3 dBm/MHz (recommended by FCC), the range will be 378 m and such a reduction represents a drastic degradation of the WiMAX performance. In this case an UWB with a power density of -91.5 dBm/MHz will reduce the

We will consider now the case of multi-UWB transmitters, assuming the case that 4 UWB are located at a distance of 1m from the WiMAX receiver. Fig. 6 shows the WiMAX downlink modulation modes as a function of the distance between the WiMAX transmitter and receiver (WiMAX link length) for three different UWB power densities. It can be noticed that, without UWB interference, the WiMAX will have a range of 1481 m for the second modulation scheme. The range will be reduced by 1% when the UWB power density is higher than -97.5 dBm/MHz. In this case, an UWB power density of -94 dBm/MHz will

**6. Results for a WiMAX system and multi UWB interferers** 

**Figure 6.** 3.5 GHz WiMAX downlink modulation modes versus distance between the WiMAX transmitter and receiver, for different UWB power densities from 4 UWB transmitters at 1 m distance to the WiMAX receiver and assuming a WiMAX transmitted power of 40 dBm/sector.

A band rejection up to 56 dB is needed for the DS-CDMA UWB system, while for the MB-OFDM UWB system a 51 dB band rejection is needed and can be obtained by nulling 16 subcarriers with a 40 dB notch filter.

We study now the same scenario but for the 2.5 GHz WiMAX. Fig. 7 shows the WiMAX downlink modulation modes as a function of the distance between the WiMAX transmitter and receiver for three different UWB power densities. It can be noticed that for the second modulation scheme without UWB interference, the WiMAX will have a range of 1817 m. At a UWB power density of -100.7 dBm/MHz, WiMAX range will be reduced by 1%.

In summary, from the results presented in Figures 2, 3, 4 and 5 it can be concluded that the power density of -41.3 dBm/MHz recommended by FCC, implies a very high range reduction, unless Detect and Avoid (DAA) techniques are implemented.

Fig. 8 represents the DAA requirement for Multiband OFDM UWB (MB-OFDM UWB) system and the Direct Sequence CDMA system (DS-CDMA UWB), with activity factors (fraction of the time they work at the 3.5 GHz band) of 32% and 100% respectively.

UWB Coexistence with 3G and 4G Cellular Systems 327

**7. Results for UMTS or CDMA-450 systems and single UWB interferer** 

power density (PUWB) of -51.3 dBm/MHz within the UMTS bandwidth.

Let us now study the coexistence of UWB systems with the UMTS (working at the 2 GHz band) and CDMA-450 systems. In the analysis we assume that the UWB data rate is higher than the UMTS or CDMA-450 chip rate. In this case, the UWB interference can be considered as a Gaussian noise. We address here the effect that the UWB system produces on the downlink of the UMTS and CDMA-450 systems. In Fig. 9, the UWB interference power on the UMTS downlink (i.e. interference as seen at the mobile) is plotted assuming a UWB

**Figure 9.** UWB interference as a function of the separation between the UWB transmitter and the UMTS

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

 **Seperation between the UMTS mobile and the UWB source (m)**

Lets us study now the case of voice service [Gp = 256 and (Eb/No)req = 6 dB] assuming an UMTS interference of -88 dBm (14 dB Rise-Over-Thermal ROT). Fig. 10 shows the downlink macrocell normalized range as a function of the separation between the UMTS mobile and the UWB transmitter for three different values of the propagation exponent γ. It can be noticed that the UWB signal creates a high interference (which reflects a macrocell normalized range reduction of 35.6%) when the separation is 1 m. For larger separation, the

Fig. 11 shows the downlink macrocell normalized capacity as a function of the separation between the UMTS mobile and the UWB transmitter. It can be noticed that the UWB signal creates a high interference (which reflects a macrocell normalized capacity reduction of 78.6%) when the separation is 1 m. For larger separation, the interference is lower and thus

interference is lower and thus the range reduction is also lower.

the normalized capacity reduction is also lower.

mobile (PUWB = -51.3 dBm/MHz).





 **UWB Interference (dBm)**





**Figure 7.** 2.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the 4 UWB transmitters and the WiMAX receiver assuming a WiMAX transmitted power of 40 dBm/sector.

**Figure 8.** DAA requirements within the 3.5 GHz band.

### **7. Results for UMTS or CDMA-450 systems and single UWB interferer**

326 Ultra Wideband – Current Status and Future Trends

dBm/sector.

0

1

2

3

4

5

 **Modulation mode**

6

7

8

9

10

**Figure 8.** DAA requirements within the 3.5 GHz band.





 **EIRP (dBm/MHz)**




**Figure 7.** 2.5 GHz WiMAX modulation modes for different UWB power densities with a 1 m distance between the 4 UWB transmitters and the WiMAX receiver assuming a WiMAX transmitted power of 40

200 400 600 800 1000 1200 1400 1600 1800 2000

 **Distance Between WiMAX Tx. and WiMAX Rx. (m)**

3.45 3.5 3.55 3.6

 **FCC Mask DS-CDMA UWB MB-OFDM UWB**

 **Frequency (GHz)**

 **WiMAX Modulation modes**

 **PUWB/MHz = -51.3 dBm PUWB/MHz = -100.7 dBm**

 **No UWB**

Let us now study the coexistence of UWB systems with the UMTS (working at the 2 GHz band) and CDMA-450 systems. In the analysis we assume that the UWB data rate is higher than the UMTS or CDMA-450 chip rate. In this case, the UWB interference can be considered as a Gaussian noise. We address here the effect that the UWB system produces on the downlink of the UMTS and CDMA-450 systems. In Fig. 9, the UWB interference power on the UMTS downlink (i.e. interference as seen at the mobile) is plotted assuming a UWB power density (PUWB) of -51.3 dBm/MHz within the UMTS bandwidth.

**Figure 9.** UWB interference as a function of the separation between the UWB transmitter and the UMTS mobile (PUWB = -51.3 dBm/MHz).

Lets us study now the case of voice service [Gp = 256 and (Eb/No)req = 6 dB] assuming an UMTS interference of -88 dBm (14 dB Rise-Over-Thermal ROT). Fig. 10 shows the downlink macrocell normalized range as a function of the separation between the UMTS mobile and the UWB transmitter for three different values of the propagation exponent γ. It can be noticed that the UWB signal creates a high interference (which reflects a macrocell normalized range reduction of 35.6%) when the separation is 1 m. For larger separation, the interference is lower and thus the range reduction is also lower.

Fig. 11 shows the downlink macrocell normalized capacity as a function of the separation between the UMTS mobile and the UWB transmitter. It can be noticed that the UWB signal creates a high interference (which reflects a macrocell normalized capacity reduction of 78.6%) when the separation is 1 m. For larger separation, the interference is lower and thus the normalized capacity reduction is also lower.

UWB Coexistence with 3G and 4G Cellular Systems 329

γ **= 3.50** γ **= 3.75** γ **= 4.00**

Next let us study the data service case [Gp = 32 dB and (Eb/No)req = 5 dB] assuming an UMTS total interference of -92.5 dBm (9.5 dB Rise-Over-Thermal ROT), representing a highly loaded macrocell. Fig. 12 shows the downlink macrocell normalized range as a function of the separation between the UMTS mobile and the UWB transmitter for three different values of the propagation exponent s. It can be noticed that the UWB signal creates a high interference (which reflects a high macrocell normalized range reduction of 50.5%) when the separation is 1m. For larger separation, the interference is lower and thus the range reduction is also lower.

 **Data Service**

**Figure 12.** Effect of the UWB interference on the macrocell normalized range as a function of the separation between the UWB transmitter and the UMTS mobile (PUWB = -51.3 dBm/MHz).

the normalized capacity reduction is also lower.

0.4

0.5

0.6

0.7

 **Downlink macrocell normalized range**

0.8

0.9

1

Fig. 13 shows the downlink macrocell normalized capacity as a function of the separation between the UMTS mobile and the UWB transmitter. It can be noticed that the UWB signal creates a high interference (which reflects a high macrocell normalized capacity reduction of 91%) when the separation is 1 m. For larger separation, the interference is lower and thus

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

 **Seperation between the UMTS mobile and the UWB source (m)**

It is obvious that such reductions (in range and capacity) are unacceptable. Thus the EIRP

Let us consider now the data service case assuming a PUWB of -81.4 dBm/MHz. Fig. 14 shows the downlink macrocell normalized range as a function of the separation between the UMTS mobile and the UWB transmitter. It can be noticed that the UWB signal creates a high interference (which reflects a high macrocell normalized range reduction) when the separation is lower than 0.25 m. For larger separation, the interference is lower and at a

power density should be reduced to get an acceptable range and capacity reduction.

distance higher than 1m, the effect of the interference is quasi null.

**Figure 10.** Effect of the UWB interference on the macrocell range as a function of the separation between the UWB transmitter and the UMTS mobile (PUWB = -51.3dBm/MHz).

**Figure 11.** Effect of the UWB interference on the macrocell normalized capacity as a function of the separation between the UWB transmitter and the UMTS mobile (PUWB = -60 dBm/MHz).

Next let us study the data service case [Gp = 32 dB and (Eb/No)req = 5 dB] assuming an UMTS total interference of -92.5 dBm (9.5 dB Rise-Over-Thermal ROT), representing a highly loaded macrocell. Fig. 12 shows the downlink macrocell normalized range as a function of the separation between the UMTS mobile and the UWB transmitter for three different values of the propagation exponent s. It can be noticed that the UWB signal creates a high interference (which reflects a high macrocell normalized range reduction of 50.5%) when the separation is 1m. For larger separation, the interference is lower and thus the range reduction is also lower.

328 Ultra Wideband – Current Status and Future Trends

0.6

20

30

40

50

60

 **Downlink normalized capacity (%)**

70

80

90

100

0.65

0.7

0.75

0.8

 **Downlink macrocell normalized range**

0.85

0.9

0.95

1

**Figure 10.** Effect of the UWB interference on the macrocell range as a function of the separation

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

γ **= 3.50** γ **= 3.75** γ **= 4.00**

 **Voice Service**

 **Seperation between the UMTS mobile and the UWB source (m)**

 **Voice Service**

**Figure 11.** Effect of the UWB interference on the macrocell normalized capacity as a function of the

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

**Seperation between the UMTS mobile and the UWB source (m)**

separation between the UWB transmitter and the UMTS mobile (PUWB = -60 dBm/MHz).

between the UWB transmitter and the UMTS mobile (PUWB = -51.3dBm/MHz).

**Figure 12.** Effect of the UWB interference on the macrocell normalized range as a function of the separation between the UWB transmitter and the UMTS mobile (PUWB = -51.3 dBm/MHz).

Fig. 13 shows the downlink macrocell normalized capacity as a function of the separation between the UMTS mobile and the UWB transmitter. It can be noticed that the UWB signal creates a high interference (which reflects a high macrocell normalized capacity reduction of 91%) when the separation is 1 m. For larger separation, the interference is lower and thus the normalized capacity reduction is also lower.

It is obvious that such reductions (in range and capacity) are unacceptable. Thus the EIRP power density should be reduced to get an acceptable range and capacity reduction.

Let us consider now the data service case assuming a PUWB of -81.4 dBm/MHz. Fig. 14 shows the downlink macrocell normalized range as a function of the separation between the UMTS mobile and the UWB transmitter. It can be noticed that the UWB signal creates a high interference (which reflects a high macrocell normalized range reduction) when the separation is lower than 0.25 m. For larger separation, the interference is lower and at a distance higher than 1m, the effect of the interference is quasi null.

UWB Coexistence with 3G and 4G Cellular Systems 331

Fig. 15 shows the downlink macrocell capacity as a function of the separation between the UMTS mobile and the UWB transmitter. It can be noticed that the UWB signal creates a high interference (which reflects a high macrocell capacity reduction) when the separation is less than 0.4 m. For larger separation, the interference is lower and at a distance higher than 1.0

Next we study the case of data service (Gp = 32 dB and (Eb/No)req = 5 dB) of the CDMA-450 3X assuming that the CDMA-450 total interference of -92.5 dBm (9.5 dB Rise-Over-Thermal ROT) and UWB power density of -95 dBm/MHz. The frequency of operation is assumed to

Fig. 16 shows the CDMA-450 downlink macrocell normalized range as a function of the separation between the CDMA mobile and the UWB transmitter. It can be noticed that the UWB signal creates a low interference when the separation is 1m which reflects a

Fig. 17 shows the CDMA-450 downlink macrocell normalized capacity as a function of the separation between the CDMA-450 mobile and the UWB transmitter. It can be noticed that the UWB signal creates a low interference when the separation is 1m which reflects a

 **Data Service**

**Figure 15.** Effect of the UWB interference on the macrocell normalized capacity as a function of the

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

 **Seperation between the UMTS mobile and the UWB source (m)**

separation between the UWB transmitter and the UMTS mobile (PUWB = -81.4 dBm/MHz).

m, the effect of the interference is to reduce the cell capacity by 1%.

normalized range reduction of less than 0.3%.

normalized capacity reduction of 1%.

90

91

92

93

94

95

 **Downlink normalized capacity (%)**

96

97

98

99

100

be 450 MHz.

**Figure 13.** Effect of the UWB interference on the macrocell normalized capacity as a function of the separation between the UWB transmitter and the UMTS mobile (PUWB = -51.3 dBm/MHz).

**Figure 14.** Effect of the UWB interference on the macrocell range as a function of the separation between the UWB transmitter and the UMTS mobile (PUWB = -81.4 dBm/MHz).

Fig. 15 shows the downlink macrocell capacity as a function of the separation between the UMTS mobile and the UWB transmitter. It can be noticed that the UWB signal creates a high interference (which reflects a high macrocell capacity reduction) when the separation is less than 0.4 m. For larger separation, the interference is lower and at a distance higher than 1.0 m, the effect of the interference is to reduce the cell capacity by 1%.

330 Ultra Wideband – Current Status and Future Trends

0

0.9

0.91

0.92

0.93

0.94

0.95

 **Downlink macrocell normalized range**

0.96

0.97

0.98

0.99

1

50

 **Downlink normalized capacity (%)**

100

**Figure 13.** Effect of the UWB interference on the macrocell normalized capacity as a function of the

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

 **Data Service**

 **Seperation between the UMTS mobile and the UWB source (m)**

 **Data Service**

**Figure 14.** Effect of the UWB interference on the macrocell range as a function of the separation

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

γ **= 3.50** γ **= 3.75** γ **= 4.00**

 **Seperation between the UMTS mobile and the UWB source (m)**

between the UWB transmitter and the UMTS mobile (PUWB = -81.4 dBm/MHz).

separation between the UWB transmitter and the UMTS mobile (PUWB = -51.3 dBm/MHz).

Next we study the case of data service (Gp = 32 dB and (Eb/No)req = 5 dB) of the CDMA-450 3X assuming that the CDMA-450 total interference of -92.5 dBm (9.5 dB Rise-Over-Thermal ROT) and UWB power density of -95 dBm/MHz. The frequency of operation is assumed to be 450 MHz.

Fig. 16 shows the CDMA-450 downlink macrocell normalized range as a function of the separation between the CDMA mobile and the UWB transmitter. It can be noticed that the UWB signal creates a low interference when the separation is 1m which reflects a normalized range reduction of less than 0.3%.

Fig. 17 shows the CDMA-450 downlink macrocell normalized capacity as a function of the separation between the CDMA-450 mobile and the UWB transmitter. It can be noticed that the UWB signal creates a low interference when the separation is 1m which reflects a normalized capacity reduction of 1%.

**Figure 15.** Effect of the UWB interference on the macrocell normalized capacity as a function of the separation between the UWB transmitter and the UMTS mobile (PUWB = -81.4 dBm/MHz).

UWB Coexistence with 3G and 4G Cellular Systems 333

**8. Results for a UMTS or CDMA-450 systems and multi UWB interferers** 

Then we study the case of multiple UWB transmitters with four UWB transmitters at a distance of 1m around the UMTS receiver. Fig. 18 shows the downlink macrocell normalized range as a function of the EIRP power density in dBm/MHz. It can be noticed that the cell

**Figure 18.** Range reduction as a function of the EIRP in (dBm/MHz) for multi UWB transmitters.

maximum allowed EIRP reduces to -101 dBm/MHz.

Fig. 19 shows the downlink macrocell normalized capacity as a function of the EIRP power density in dBm/MHz. It can be noticed that, for a capacity reduction of only 1%, EIRP should be -87.4 dBm/MHz. this represents a 6 dB reduction equal to [10log10(4)], where 4 is the number of the UWB sources. The conclusion is that, for the case of single UWB transmitter, the UMTS can easily tolerate the UWB interference when the UWB EIRP is lower than -81.4 dBm/MHz for 1m distance between the UWB transmitter and the UMTS mobile. For the multi UWB transmitter case, the UMTS can easily tolerate the UWB interference when the UWB EIRP is -87.4 dBm/MHz. When using a CDMA-450 system the


 **EIRP (dBm/MHz)**

Table 2 presents the maximum allowed EIRP for different frequency bands, for UWB activity factor of 100% and multi UWB transmitter scenario, for two different cases, (case A with 99.995% confidence and case B with 99% confidence respectively). Table 3 represents the maximum allowed EIRP for different frequency bands for UWB activity factor of 10%

and multi UWB transmitter scenario for the two previous cases A and B.

range reduction is always lower than 1%.

0

0.1

0.2

0.3

0.4

0.5

 **Range reduction (%)**

0.6

0.7

0.8

0.9

1

**Figure 16.** Effect of the UWB interference on the macrocell normalized range as a function of the separation between the UWB transmitter and the CDMA450 mobile (PUWB = -95 dBm/MHz).

**Figure 17.** Effect of the UWB interference on the macrocell normalized capacity as a function of the separation between the UWB transmitter and the CDMA450 mobile (PUWB = -95 dBm/MHz).

#### **8. Results for a UMTS or CDMA-450 systems and multi UWB interferers**

332 Ultra Wideband – Current Status and Future Trends

0.95

95 95.5 96 96.5 97 97.5 98 98.5 99 99.5 100

 **Downlink normalized capacity (%)**

0.955

0.96

0.965

0.97

0.975

 **Downlink macrocell normalized range**

0.98

0.985

0.99

0.995

1

**Figure 16.** Effect of the UWB interference on the macrocell normalized range as a function of the separation between the UWB transmitter and the CDMA450 mobile (PUWB = -95 dBm/MHz).

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

γ **= 3.50** γ **= 3.75** γ **= 4.00**

 **Data Service**

 **Seperation between the CDMA-450 mobile and the UWB source (m)**

 **Data Service**

**Figure 17.** Effect of the UWB interference on the macrocell normalized capacity as a function of the separation between the UWB transmitter and the CDMA450 mobile (PUWB = -95 dBm/MHz).

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

 **Seperation between the CDMA-450 mobile and the UWB source (m)**

Then we study the case of multiple UWB transmitters with four UWB transmitters at a distance of 1m around the UMTS receiver. Fig. 18 shows the downlink macrocell normalized range as a function of the EIRP power density in dBm/MHz. It can be noticed that the cell range reduction is always lower than 1%.

**Figure 18.** Range reduction as a function of the EIRP in (dBm/MHz) for multi UWB transmitters.

Fig. 19 shows the downlink macrocell normalized capacity as a function of the EIRP power density in dBm/MHz. It can be noticed that, for a capacity reduction of only 1%, EIRP should be -87.4 dBm/MHz. this represents a 6 dB reduction equal to [10log10(4)], where 4 is the number of the UWB sources. The conclusion is that, for the case of single UWB transmitter, the UMTS can easily tolerate the UWB interference when the UWB EIRP is lower than -81.4 dBm/MHz for 1m distance between the UWB transmitter and the UMTS mobile. For the multi UWB transmitter case, the UMTS can easily tolerate the UWB interference when the UWB EIRP is -87.4 dBm/MHz. When using a CDMA-450 system the maximum allowed EIRP reduces to -101 dBm/MHz.

Table 2 presents the maximum allowed EIRP for different frequency bands, for UWB activity factor of 100% and multi UWB transmitter scenario, for two different cases, (case A with 99.995% confidence and case B with 99% confidence respectively). Table 3 represents the maximum allowed EIRP for different frequency bands for UWB activity factor of 10% and multi UWB transmitter scenario for the two previous cases A and B.

It shall be mentioned that if the critical distance is reduced from the 1m already considered down to 0.5m, the maximum accepted UWB power densities should be decreased by 6 dB from the values given before.

UWB Coexistence with 3G and 4G Cellular Systems 335

The coexistence of UWB with 3G and 4G Cellular Systems has been studied in this chapter. In particular UMTS in the 2 GHz and in the 450 MHz (CDMA-450) frequency bands have been selected as examples of 3G cellular systems and the WiMAX system as example of 4G. The methodology used to account for the impact of UWB interference on the coverage range and capacity of the interfered systems has been explained in detail. Finally it has been

From the above given results we can conclude that the spectrum mask proposed by the FCC for indoor application (-51 dBm/MHz in the UMTS band and -41 dBm/MHz for the CDMA-450 band) is very high and cannot be tolerated by the mobile systems. From the results obtained we conclude that another spectrum mask with lower UWB power density has to be used.

[1] Ahmed B. T., Ramon M. C. & Ariet L. H., 2004, "Impact of Ultra Band (UWB) on Macrocell Downlink of DCS-1800 and GSM-900 Systems", Radioenginnering, Vol. 14,

[2] Ahmed B. T., Ramón M. C., 2008, "On the Impact of Ultra-Wideband (UWB) on Macrocell Downlink of UMTS and CDMA-450 Systems", IEEE Electromagnetic

[3] Ahmed B. T., Campos JL. M., Cruz J. C, 2010, "Impact of Ultra Wide Band emission on WiMAX systems at 2.5 and 3.5 GHz", Computer Networks, Vol. 54, pp.1573-1583. [4] Ciccoganini W., Durantini A., and Cassioli D., 2005, "Time domain propagation measurements of the UWB Indoor Channel Using PN-Sequence in the FCC-Compliant Band 3.6-6 GHz", IEEE trans. Antennas and Propagation, Vol. 53, No. 4, pp. 1542-1549. [5] Giuliano R., Mazzenga F., Vatalaro F., "On the interference between UMTS and UWB systems", pp: 339 – 343, IEEE Conference on Ultra Wideband Systems and

[6] Chiani M, and Giorgetti A, "Coexistence between UWB and Narrow-Band Wireless Communication Systems", Proceedings of the IEEE, Vol. 97, No. 2, February 2009, pp.

[7] Chóliz J, Hernández A, Alastruey I and Valdovinos A, "Coexistence and interworking between UMTS and UWB: a performance evaluation of a UMTS/UWB interoperability

platform", Telecomunication systems, Vol. 49, No. 4, pp. 409-420.

applied in a set of study cases in scenarios involving the 3G and 4G selected systems.

**9. Conclusions** 

**Author details** 

Ahmed Bazil Taha

Miguel Calvo Ramon

**10. References** 

231-254.

No.1, pp. 51-55.

*Universidad Autonoma de Madrid, Spain* 

*Universidad Politecnica de Madrid, Spain* 

Compatibility, Vol. 5, No. 2, pp. 406-412.

Technologies, 2003 , 16-19 Nov. 2003.

**Figure 19.** Capacity reduction as a function of the EIRP in (dBm/MHz) for multi UWB transmitters.


**Table 2.** Maximum allowed EIRP for different frequency bands with UWB activity factor of 100%.


**Table 3.** Maximum allowed EIRP for different frequency bands with UWB activity factor of 10%.
