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System architecture D2.4

D2.4 – System architecture

Project acronym CORTIF

Project title Coexistence Of RF Transmissions In the Future

Programme CATRENE – CA116Start date of the project 01.07.2014Duration 36 months

Deliverable reference number D2.4Deliverable title System architectureWP contributing to the deliverable WP2Due date M12Actual submission date 22-10-2015

Responsible organisation TECHNICOLOR Jean-Yves Le NaourAuthors TECHNICOLOR,

AIRBUS DS SAS, BUT, IMA IMT NXP-FR XLIM IMEC-NL

Peer reviewer Technolution Abstract Report on system architectures Keywords Coexistence, LTE, Wi-Fi, ZigBee, BLE,

DVB-T/T2,868MHz.

Dissemination level Confidential Revision – Version 0.5

System architecture 1/48


Table of Contents1 Introduction.........................................................................................................62 About this document...........................................................................................73 Use cases............................................................................................................83.1 HEALTHCARE1: Wireless Healthcare............................................................................83.1.1 Architecture descriptions......................................................................................8

3.1.1.1 BLE network architecture under interference.....................................................83.1.1.2 BLE system architecture for interference mitigation: BLE vs. Wi-Fi interference example..........................................................................................................................9

3.1.2 ZigBee Healthcare WSN with Localization..........................................................103.2 WSN_PERTURBATION: Perturbation of Wireless Sensor Network................................123.2.1 Motivation..........................................................................................................123.2.2 Coexistence techniques.....................................................................................14

Spatial decoupling.........................................................................................................14Decoupling in the frequency domain.............................................................................15Time-based decoupling.................................................................................................15Media access selection..................................................................................................15Cognitive co-existence..................................................................................................16Radio Performance Optimisation...................................................................................16Sensing receiver............................................................................................................21

3.3 PMR: Professional Mobile Radio (PMR).......................................................................243.3.1 System decomposition.......................................................................................243.3.2 Physical hardware architecture..........................................................................27

NB Mobile path..............................................................................................................28BB Mobile path (LTE UE – HPM).....................................................................................30

3.4 HOMEDEVICE: Multimode Multi-standard Smart Home Device...................................333.4.1 RF Architecture description................................................................................333.4.2 Justification.........................................................................................................36

3.4.2.1 Wi-Fi/LTE B7.....................................................................................................363.4.2.2 868MHz/LTE B20............................................................................................363.4.2.3 WiFI/BT...........................................................................................................373.4.2.4 WiFI/ZigBee....................................................................................................37

4 Measurement techniques : Coexistence of cellular, wireless and broadcasting networks................................................................................................................... 38

4.1.1 Cellular and WLAN..............................................................................................384.1.2 Cellular and DVB................................................................................................394.1.3 Cellular and DVB with CR support......................................................................414.1.4 ZigBee vs Wi-Fi...................................................................................................414.1.5 Bluetooth Low Energy (BLE) and Wi-Fi................................................................43

5 Conclusions.......................................................................................................456 References........................................................................................................467 List of Abbreviations..........................................................................................47



Version Control

Date Author Version

Notes

March 2rd 2015 Jean-Yves Le Naour (TECHNICOLOR)

0.10 Initial draft Version

March 12th 2015 Jean-Yves Le Naour (TECHNICOLOR)

0.20 Updated draft Version

June 10th 2015 Jean-Yves Le Naour (TECHNICOLOR)

0.30 Updated with partners contributions

July 21st 2015 Jean-Yves Le Naour (TECHNICOLOR)

0.4 Updated with last partners contributions

October 9th 2015 Jean-Yves Le Naour (TECHNICOLOR)

0.5 Updated after review



List of tables

Table 1. Building blocks specifications..................................................................................24Table 2: List of major system elements.................................................................................26Table 3: High level description of the different elements......................................................29Table 4: Interfaces for the PMR Coexistence Box..................................................................30Table 5: Foreseen interfaces from the PMR Coexistence System perspective......................33Table 6: Summarized antenna isolation requirements..........................................................37

List of figures

Figure 1: BLE network together with other sources of interference such as Wi-Fi/WLAN and neighbour BLE.................................................................................................................8

Figure 2 : BLE channels co-existence with Wi-Fi channels.......................................................9Figure 3: Rx receiver chain...................................................................................................10Figure 4 : Architecture diagram of proposed healthcare WSN...............................................11Figure 5: Block diagram of healthcare WSN node with two integrated modules for BLE and

ZigBee and coexistence measuring architecture...........................................................12Figure 6: Example of interferences in a Zigbee Network.......................................................13Figure 7 - Scan Analysis NXP Lab over night.........................................................................14Figure 8 : Signal spreading and dispreading can help to improve SNR and to reduce the ef-

fect of interferers...........................................................................................................16Figure 9: :Receiver architecture............................................................................................17Figure 10: Illustrations of WiFI/Zigbee co-existence..............................................................18Figure 11: Global receiver architecture.................................................................................18Figure 12 : Receiver scheme.................................................................................................19Figure 13 : JN5168 block diagram (ZigBee only)...................................................................20Figure 14 : ZigBee/BLE Receiver simplified block diagram....................................................21Figure 15: Conceptual schematic based on a sensing receiver.............................................21Figure 16 : Architecture of the sensing receiver...................................................................22Figure 17 : Architecture of the ADC..................................................................................22Figure 18 : Architecture of the ADC..................................................................................23Figure 19: The inherent anti-alias filter transfer function of the CT modulator.................23Figure 20: PMR system view with structural elements of the Vehicle System (one basic con-

figuration on the BB side, with IP clients & applications only).......................................25Figure 21: PMR Vehicle System view.....................................................................................27Figure 22 : Internal block diagram of the PMR Coexistence Box...........................................28Figure 23 : High level internal block diagram of the RF Front-End stage of the LTE UE-HPM.30Figure 24: PMR Coexistence Box...........................................................................................31Figure 25: Global architecture of a multimode multi-standard smart home device...............34Figure 26: Smart Home device floor plan.............................................................................34



Figure 27: Detailed Home device system architecture.........................................................35Figure 28 : Proposed general block diagram of workplace for measuring the interaction

between 2G and 3G wireless networks in a) real World environment and in b) laboratory conditions......................................................................................................................39

Figure 29: Proposed general block diagram of workplace for measuring the interaction between different DVB services and LTE networks in a) real World environment and in b) laboratory conditions ([3], [6])..................................................................................40

Figure 30: General block diagram of proposed workplace for measurements of the interac-tion between ZigBee (IEEE 802.15.4) and the IEEE 802.11b/g/n networks in a) real World environment and in b) laboratory conditions (based on [10])..............................42

Figure 31 : General block diagram of proposed workplace for measurements of the interac-tion between BLE (Bluetooth v. 4.1) and the IEEE 802.11b/g/n networks in a) real World environment and in b) laboratory conditions.................................................................44



1 Introduction

CORTIF targets the concurrent use of radio spectrum by multiple applications without detrimental mutual interference. It is applicable both at the application level (systems sharing the same location) and technology level (systems sharing the same PCB). Application companies (Mobile and Set-Top Box developers) within the consortium define the system requirements and constraints. Semiconductor suppliers together with universities will develop the technical approaches and integrators will create and demonstrate working proof-of-concept level solutions highlighting the achievable improvement considering metrics such as throughput, RF standardization, power consumption and bill of material requirements.There are expected to be 7 trillion wireless devices in the field by 2020. These will cover not only telecommunications but also new application areas such as e-health, traffic management and environmental monitoring. The Wireless World Research Forum predicts that each person will use up to one thousand wireless devices by this date. The interference problems that will emerge in such a rich environment urgently need to be addressed. This issue is becoming increasingly important for the European economy. Without action a complete wireless traffic jam is expected in the near future.CORTIF will enable the concurrent use of RF spectrum by multiple, independent radio systems without harmful mutual interference. It is applicable across distances of different orders of magnitude; from a single PCB out to the wide area with radios that might be far apart.



2 About this documentThis document forms part of CORTIF Work Package 2 with the main objectives to setup and define the structure of the System architecture project.

In the task 2.3, the different system architectures will be defined that will lead sys-tems that will be able to coexist with each other, based on the requirements defined in Task 2.2, such as architectures for:

WLAN RF for GWs and clients. Design for emerging mobile, broadcast and wireless systems platform and its

general environments. Targeted NB-BB equipment for the Public Safety application (vehicular and

portable devices). Digitally enhanced receivers with interference reduction and out-of-band

blocker attenuation capability - System-level definition of the ADC architec-ture (core of the ADC is built around a continuous-time Delta Sigma modu-lator with a robust STF).

Application of coexistence techniques on filtering, down conversion and AGC strategy; deep architecture analysis to significantly reduce consumption (fil-ters redundancy reduction...)

SW and HW design for multi-radios STB/GW. System level definition of interference mitigation baseband (BB) for health-

care applications. Definition of IP in order to achieve requirements on TV applications.

This document define the architecture for the mobile, broadcast and wireless sys-tems platforms and its general environments. It also define the system level inter-ference mitigation in the basebands. Application of coexistence techniques are con-sidering on filtering, down conversion and AGC strategy with deep architecture ana-lysis to significantly reduce consumption (filters redundancy reduction...). The archi-tecture of WLAN RF for gateways and clients, the NB-BB equipment for the public safety application (vehicular and portable devices), ADC and digitally enhanced re-ceivers with interference reduction and out-of-band blocker attenuation capability are presented.

The chapter 3 deals with the different addressed use cases which are : Wireless Healthcare Perturbation of Wireless Sensor Network Professional Mobile Radio Multimode Multi standard Smart Home Device

Measurement techniques related to coexistence of cellular, wireless and broadcasting networks and measurement techniques are presented in chapter 4



3 Use cases Following the CORTIF Requirements document (D2.3), the different use cases are listed and for each the proposed system architecture is detailed in this section. This section will be split into several sub-sections dedicated to the different selected use cases

3.1 HEALTHCARE1: Wireless HealthcarePersonal Area Network Applications such as fitness trackers, patient trackers, micro location or orientation sensors are taking advance of the Bluetooth Low Energy (BLE) eco-system which is already deployed in the majority of smartphones or other BLE enabled devices on the market. Since healthcare services should be reliable, the interference issues on industrial, scientific and medical (ISM) 2.4 GHz band, where BLE operates, should be mitigated. Main sources of interference are coming from 2.4GHz interferers (WiFi, Zigbee, Bluetooth Low Energy) or Out of band interference (cellular communications).

3.1.1 Architecture descriptions

3.1.1.1 BLE network architecture under interferenceError: Reference source not found presents a master BLE node maintaining two connections with two corresponding slave/peripheral BLE nodes. Next to BLE network, sources of interference might be present such as neighbour BLE networks and Wi-Fi, operating on 2.4 GHz as well.

Figure 1: BLE network together with other sources of interference such as Wi-Fi/WLAN and neighbour BLE

Given the co-existence of different systems in the surrounding of a personal area network, we consider the typical interference scenarios for healthcare applications:

BLE under test vs. BLE interferer BLE under test vs. Wi-Fi interferer



BLE under test vs. ZigBee interferer BLE under test vs. cellular technologies (for example LTE interferer)

The main parameters of a BLE device that should be observed are as follows: Received signal strength (RSSI) Adjacent/alternate channel rejection ratio Packet error rate (PER)

3.1.1.2 BLE system architecture for interference mitigation: BLE vs. Wi-Fi interference example

Figure2 Error: Reference source not found presents an example of interference of BLE over Wi-Fi interference. BLE standard has selected as advertising channels (green colour), channels that they do not overlap with Wi-Fi channels. The rest of the BLE channels, the data channels, might overlap with the Wi-Fi channels and therefore, a way for achieving co-existence on BLE network with other radio technologies should be introduced.

Figure 2 : BLE channels co-existence with Wi-Fi channels

For the BLE system itself, it is possible to use all the 40 channels defined by the standard at the ISM band. However, depending on the co-existence scenario, there might be a strong Wi-Fi interferer in the neighbour. As shown in Figure2Error:Reference source not found, three commonly used Wi-Fi channels pollute the bands for the BLE radio. Algorithms are to be developed to avoid such channels that are occupied by the Wi-Fi signals, and just to employ a sub-set of the available BLE channels to set up more reliable BLE links. Therefore, using the information (Receiver signal, strength, clear channel assessment, packet error rate, etc.) coming from Digital Baseband (DBB) of the receiver, after processing information coming from Analog Front End (AFE) we will characterize the BLE channels in “good” and “bad”, and executing the BLE frequency hopping over the “good” channels. Figure 3Error: Reference source notfound presents the RX part of the digital baseband (DBB) consists of the RX physical layer (PHY), RX data link layer (DL) and control modules. In another word, the RSSI information acquired from RX PHY will be forwarded to the upper layers to be used as the information to define the customized channels for a certain application scenario in order to avoid the interference from other systems.



Figure 3: Rx receiver chain

3.1.2 ZigBee Healthcare WSN with Localization

A combination of Bluetooth Low Energy (BLE) and ZigBee communication technolo-gies, which both operate in the ISM band 2.4 GHz, is considered in application of healthcare wireless sensor network designed for monitoring and positioning of sensor units. Architecture of this system is presented in diagram Fig. 4. System con-sists of back-bone wireless network connecting nodes and central system by using ZigBee communication mode and wireless sensors monitoring different physical quantities and states of patient or medical equipment. The sensors communicate with nodes (e.g. one node per room) by BLE communication mode, which can be also effectively used for sensor localization based on RSS measurement. An applica-tion of the adaptive frequency hopping technique used in the BLE standard brings more reliable determination of the signal level at the receiver side as well as more precise sensor localization. Crucial issue of this system in light of coexistence is close placement of ZigBee and BLE transceiver in WSN node.



Figure 4 : Architecture diagram of proposed healthcare WSN.

The principal block diagram of healthcare WSN node and measurement setup for evaluation of the coexistence between spatially close implemented transceivers for BLE (Microchip RN4020) and ZigBee (NXP JN5148) communication standard is shown in Fig. 4. The aim of this measurement is clear specification of transfer per-formances in back-bone link (BLE interference to ZigBee) and also in sensor-to-node link (ZigBee interference to BLE) in dependence of distance and mutual orientation of antennas in the node unit to optimization of inside arrangement of used modules in light of maximum data throughput and precise localization of the sensor.

The main parameters of BLE (node-to-sensor) link which shall be observed are follows:

Power level of the RF signal Bit Error Ratio (BER) – raw errors (in channel) Data transmission efficiency – limitation of data rate.

The main parameters of ZigBee (back-bone) link which shall be observed are follows:

Power level of the RF signal Bit Error Ratio (BER) – raw errors (in channel). Data transmission efficiency – limitation of data rate.



Figure 5: Block diagram of healthcare WSN node with two integrated modules for BLE and ZigBee and coexistence measuring architecture.

3.2 WSN_PERTURBATION: Perturbation of Wireless Sensor Network

3.2.1MotivationWireless Sensor Networks (WSN) based on ZigBee or Bluetooth Low Energy of prone to be perturbed with concurrent Radio transmissions coming from other ZigBee or Bluetooth Low Energy WSN, or from other video streaming systems based on Wi-Fi or from cellular communications (3G at 2.1GHz frequency or 4G at 2.7GHz frequency).The 2.4 GHz ISM band is a frequency band which enjoys a near global availability on the understanding that ISM band equipment designed to operate in the band must share it with other systems. In particular modern IEEE802.11 (WiFi) systems are rapidly becoming IEEE802.11g/n enabled. Careful consideration of frequency bands, radio power levels and system timings will ensure that IEEE802.15.4 can co-exist with its Wi-Fi neighbours. Coexistence topic is even more crucial considering spa-tially limited networks nature got with Wi-Fi, ZigBee or Bluetooth. On the top we can add close cellular communication with those networks.



Figure 6: Example of interferences in a Zigbee Network

Due to the extensive use of the 2.4 GHz ISM band is a frequency band, it is not pos-sible to completely rule out the all set of mutual influence of wireless systems oper-ating in parallel. These radio influences may lead to restrict availability of individual systems.

In this report intention is to list how to avoid / limit mutual wireless interference and to implement interference free parallel operation.

The ISM band used by NXP IEEE802.15.4 products is wide at approximately 80 MHz in most territories (2400-2482.5 MHz). This is certainly wide enough to contain many different radio systems none of which will use more than 50% of the available band at any one time. Indeed the rules governing ISM band worldwide seek to en-sure that radio systems can indeed share the band. As a consequence there will ex-ist some conditions in which IEEE802.15.4 can effectively co-exist with IEEE802.11g/n.

Of primary interest in this study is the presence of signals that occupy the 2.4 GHz ISM band that are likely to collide with IEEE802.15.4 traffic. However, it is clear that the spectrum is now used by higher bandwidth IEEE802.11g and IEEE802.11n ver-sions of "Wi-Fi" and they are becoming widely deployed worldwide.

Influencing of radio operation can only occur if several systems are transmitting At the same location, At the same time, At the same frequency.

For instance low Wi-Fi traffic activity decreases likehood that IEEE802.15.4 will encounter interference.

Moreover, as another illustration, high Wi-Fi transmit power increases likehood that IEEE802.15.4 will encounter significant blocking interference when close to Wi-Fi transmitter.Of course observations regarding Wi-Fi and ZigBee coexistence issues and solution can be extended to the case of other standards coexistence.



Figure 7 - Scan Analysis NXP Lab over night

3.2.2Coexistence techniques

Essentially, the conclusions still apply qualitatively in that the presence of IEEE802.11g/n will require consideration of:

Physical separation of IEEE802.11 & IEEE802.15.4 equipment. Radio isolation of IEEE802.11 & IEEE802.15.4 equipment Time occupancy and frequency channel occupancy of IEEE802.11 &

IEEE802.15.4 traffic.

Minimisation of radio influences is considered in more details hereafter. The aim is to decouple the wireless systems in at least one of the sectors (location, frequency or time) or to introduce counter-measure technics (media access selection, AGC/fil-tering…) when previous solution not possible, so that desired operation of the sys-tems involved is guaranteed.

WITH CAREFUL SYSTEM ENGINEERING AND GOOD AVAILABLE COUNTERMEASURE RESOURCES WIFI DISRUPTION CAN BE MINIMISED OR EVEN ELIMINATED.

Spatial decoupling

For instance in order to isolate IEEE802.11g/n transmitter from IEEE802.15.4 re-ceiver as much as possible

Adaptation of the transmitted power. For instance, minimise the WiFi Tx power seen by IEEE802.15.4 receiver,

Use spatial separation if possible, Careful use of antennas (cross-polar, good positioning, beamforming with null

aligned on perturbation source).System architecture 14/48


Decoupling in the frequency domainFor instance in order to isolate IEEE802.11g/n system from IEEE802.15.4 system as much as possible

Avoid IEEE802.11g/n channel frequency being co-incident with IEEE802.15.4 channel(s),

LOW IEEE802.15.4 BANDWIDTH ALLOWS FREE CHANNEL SPACE IN ISM BAND TO BE UTILISED,

Carefully plan the best IEEE802.15.4 channel to use, Blacklisting of frequency ranges or channels, Build continuous adaptation into IEEE802.15.4 system thanks to continuously

tracking as regular scans can detect local changes in interference. Studies have shown rapid changes in interference within daily and weekly patterns.

Time-based decoupling

Such an effective Wi-Fi Countermeasures are

Average loading of all individual systems as low as possible, Minimization of frequency utilization over time.

For instance in order to isolate IEEE802.11g/n system from IEEE802.15.4 system as much as possible

Set ZigBee packet size & CCA (clear channel assessment) mechanism in order to utilise available time windows,

Many Wi-Fi networks are idle a lot of the time, Use the time when Wi-Fi is not present to send IEEE802.15.4 packets, Avoid using very ZigBee long packets.

Media access selectionVarious techniques for media access are used with different properties regarding the sensitivities of a radio system to environmental influences and systems operat-ing in parallel

Bluetooth uses frequency hopping spread spectrum (FHSS). Then the trans-mitter frequency hops in accordance with a rule known by the receiver. As a result interferences only affect a part of the transmitted data, so that only a small portion has to be retransmitted,

ZigBee uses direct sequence spread spectrum (DSSS), the bandwidth re-quired for the radio link is spread using chipping sequence by which the data signal is multiplied. This chipping sequence makes the transmission less sensitive to narrow-band interference. Unfortunately Wi-Fi is wideband inter-ferer.



Figure 8 : Signal spreading and dispreading can help to improve SNR and to reduce the effect of interferers

Cognitive co-existenceFor instance for co-located IEEE802.11g/n and IEEE802.15.4 systems a suggestion is to explore whether the two systems can interact at the application or MAC layers to minimise collisions (time multiplex operation).

For instance, high throughput achieved by IEEE802.11n could allow clear “windows” to be engineered that IEEE802.15.4 could exploit without seriously compromising performance. Cognitive coexistence is an emerging area of development that has been used in other systems. This kind of operation is quite usual per today within SoC supporting Wi-Fi and BLE links in concurrent way.

Radio Performance OptimisationAccording to previously described technics, two radio systems can be decoupled in the frequency domain. Typically Wi-fi and 802.1.5.4 would use non-overlapping channels, hence both the communications can co-exist. However, if the interfering Wifi transmitter is located very close to the 802.15.4 receiver, this causes the front end of the receiver to go in saturation despite the use of non-overlapping channels. This is because of the high interference power. Figure below shows a generic receiver path block diagram. The received signal goes thru a channel filter, which removes the out of channel interference. Hence, the modem sees only the desired 802.15.4 signal. AGC algorithm in the modem works based on the strength of the desired signal. Since it sees the desired strength as low, it sets the GAIN value as “HIGH”.But, since there is already a high power Wifi interference signal present, this “HIGH” GAIN causes the blocks before the filter to go into saturation (first stage of filter saturates too possibly). This results in non-linear distortion of the input signal, which results in the Packet Errors to increase.



Figure 9: :Receiver architecture

The second order nonlinearity of the receiver will square the modulated blocker signal, such as the Wi-Fi signal, producing DC and low frequency components which fall into the receive band of the direct conversion receiver. This case is more stringent when far-off Wi-Fi interferer. So it’s applicable too when ZigBee receiver is polluted by out-of-band blockers like cellular signal. These later are possibly partially attenuated by the antenna ISM band filtering.In the same way the third order nonlinearities will produce spurious components around the Wi-Fi blocking signal and possibly they fall into the receiver band if ZigBee signal if close enough from Wi-Fi blocker in frequency domain.As a results, noise level in the receive band increases and overall sensitivity of the receiver rises.

A(f)

f

A(f)

f

Wi-Fi transmitted Signal IF+BB

filterZigBee Signal to receive

Wi-Fi transmit Signal Leaks to

Receiver demodulator

In-band IM2 power due to Wi-Fi TX

A(f)

f

A(f)

f

ZigBee Signal to receive

IF+BB filter

Wi-Fi transmitter Noise falling into Receiver Band

Wi-Fi transmitted main lobe Signal

In-band IM3 power due to Wi-Fi TX

Wi-Fi transmit Signal Leaks to

Receiver demodulator

Figure 10: Illustrations of WiFI/Zigbee co-existence



The situation is worst when the desired 802.15.4 signal is of very low power and the interference is of high power. Indeed, the signal can fall below the increase noise floor due to intermodulation products. The RF coexistence scheme that will be studied in the CORTIF project context addresses this issue.A solution to this problem is to detect the presence of out of channel Wi-FI blocker and provide this information to modem. If the out of channel Wi-FI blocker detection is available with the Modem, it can restrict the GAIN to “LOWER” even if the desired signal is of lower power. This will avoid saturation and improve Packet Errors in presence of strong Wi-Fi interference.Although Noise Figure of the system is higher in case of “LOWER” Gain compared to HIGH gain, the degradation of input signal due to saturation is far worse than due to higher Noise Figure. Hence, the reception of the signal would be much better by using the above mentioned scheme in the presence of strong Wi-Fi interference.The input signal power measurement has to be wideband covering entire ISM band. This is required to measure the entire blocker signal power.Figure below provides an overview of how the receiver block diagram looks like with this technics.

Figure 11: Global receiver architecture

This technique deals with an effective AGC strategy in order to relax front-end linearity and filtering requirement. It results a significant reduction current consumption & cost (filters redundancy reduction...).This receiver targets to improve first the reliability of operation of a wireless sensor network operating in the 2.4GHz ISM band. But of course of course has the front is broadband then this AGC strategy improves out-of-band coexistence too, like in the case of cellular system interferences (3G, 4G).The above scheme was validated using system simulation. The system simulation is described in figure below. Radio Receiver Model and Simulation Environment have been set-up based on ADS / Cadence Tool. Only a model of the base-band radio incorporating the linearity/noise performance of the RF front end was implemented in order to perform a timed-domain system level simulation of the 2.4GHz RF carrier receiver with acceptable computation time.



Figure 12 : Receiver scheme

Only coexistence between Wi-Fi and ZigBee based WSN has been explored for far. The scheme is applicable to BLE based WSN too. More elaborate system simulation would be carried during the execution stage of the project in order to explore other coexistence cases.A proof of concept of the dedicated algorithm has been determined in order to select the best AGC settings regarding the radio activity. The algorithm operates on the current and previous stored samples to predict if Wi-Fi blocker would be present during OFF time. The main difficulty of the system is the WSN radio is most of the time in standby, so without any possibility to pursuit a continuous scan of the radio medium. But the same radio has to be able to detect the presence of blocker quickly at wake-up. The difficulty is even higher considering the coexistence countermeasure mustn’t impact significantly the current consumption. A battery-powered WSN node must operate for a while.Proof of concept has been validated by embedding a wideband detector with its dedicated algorithm within an existing JN5168 ZigBee SoC without changing the receiver signal path design.



Figure 13 : JN5168 block diagram (ZigBee only)

Measurement results have shown a good match with system simulation. Radio link budget range is improved while keeping unchanged the existing radio channel, just by Wi-Fi countermeasure algorithm aided AGC.These results allows to secure the next step which is to design of a dual mode ZigBee/BLE receiver implementing interferer’s counter-measures enabling to mitigate coexistence issues with 2.4GHz ISM band interferers like Wi-Fi technology while keeping minimum current consumption target.This dual mode receiver will be embedded within a SoC looking like a JN5168 device. The building blocks are interferers sensing and filtering techniques coupled to the AGC.


Existing ZigBee transceiver whose receiver implements interferer’s counter-measures proof of concept


Figure 14 : ZigBee/BLE Receiver simplified block diagram

Sensing receiver

An approach based on spectrum sensing was proposed conjointly by IMT and NXP. This solution is illustrated in Figure 15. The idea is to embed in the Zigbee coordinator a radio receiver that scans the whole RF band ranging from 2400 to 2482.5 MHz in order to detect the free channels in the 2.4GHz spectrum. In this way, the coordinator knows his environment and can choose the right channel to communicate with the end devices.Because the coordinator is mains powered, the cost of the sensing receiver is more critical than its power consumption.

Figure 15: Conceptual schematic based on a sensing receiver



To reduce as much as possible the cost of the sensing receiver, a “digital” architecture was proposed. It is shown in figure 16. Analog baseband functions such as variable gain amplifier (VGA) and channel filters were replaced by a high dynamic range ADC. Instead, the selection of channels is done in the digital domain which is less costly.However, the down-converted I&Q channels needs a minimum amount of filtering to avoid that unwanted signals fall back into baseband (aliasing). To deal with this issue, the architecture of the ADC is based on a Continuous-Time (CT) Delta-Sigma () modulator due to its intrinsic anti-aliasing filtering property.

Figure 16 : Architecture of the sensing receiver

The general architecture of the ADC is shown in figure 6. In this project, we have focused on the critical part of the ADC which is the CT modulator. This block will be implemented in a 65nm CMOS process from ST Microelectronics. Its architecture is detailed in figure 17.

Figure 17 : Architecture of the ADC



Figure 18 : Architecture of the ADC

An OSR of only 8 is chosen to reduce the speed requirement of the loop filter and the multi-bit quantizer which results in a low power consumption of the analog part. As the maximum input signal bandwidth is 40MHz, the modulator is clocked at a fixed frequency of 640MHz. To compensate for the lower noise-shaping performance at low-OSR, a 5th-order NTF with a maximum gain (Qmax) of 12dB and a 5-bit quantizer are combined to keep the quantization noise level well below the ADC noise floor which is dominated by the thermal noise of the modulator front end.

As shown in figure 19, the alias attenuation obtained with the intrinsic loop filter of the modulator is equivalent to what would be obtained with a third-order Butterworth filter.

Figure 19: The inherent anti-alias filter transfer function of the CT modulator

The main system- level specifications of each sub-blocks of the modulator are summarized in Table 1.


PARAMETERS VALUE UNITLoop filter

Coefficients mismatch () 1 %Unit gain frequency accuracy ±2 %Opamp1 GBW 6 fs

Opamp1 dc gain ≥40 dBMain DAC

Current mismatch 0.2 %Clock jitter 450 fsOutput impedance >1 MΩ

Quantizer

Offset () 2 mVHysteresis >2 mV


Table 1. Building blocks specifications

3.3 PMR: Professional Mobile Radio (PMR)

This section is focusing only on high level physical architectures covering: The decomposition in system elements, The list of external interfaces, The system elements to be specified and designed at lower levels for the

mitigation solution of the mutual coexistence issue.

3.3.1 System decomposition The diagram below illustrates the basic composition of a PMR NB&BB system including among others the PMR Vehicle System.



bdd [Package] PMR System [PMR NB&BB System]

«block»PMR System

«block»PMR NB System

«block»PMR BB System

«block»PMR Vehicle System

«block»PMR LTE Network

«block»PMR NB Network

LTE UE - HPM NB Mobile

«block»PMR Vehicle System::PMR Coexistence Box

«block»PMR Vehicle System::PMR

Coexistence System

Vehicle_Power_Supply

IP Clients & Apps

1

1

1..*

1

1

1

11

11

1

1

1

1

1..*

1

1..*

1

1

1

1

1

1

Figure 20: PMR system view with structural elements of the Vehicle System (one basic configuration on the BB side, with IP clients & applications only)

The basic configuration of the PMR Vehicle System, supporting both NB and BB radio access technologies, includes IP clients and applications, the Power Supply unit, the LTE UE High Power Modem (LTE UE – HPM), the NB Mobile (and its associated accessories) and the PMR Coexistence System and Box.

The list of major system elements is described in the following table:System element (actors for some

of them)Description

PMR LTE network - Professional Mobile LTE network providing private internet/intranet access to LTE UE – HPM device(s). Includes eNodeB, ePC, IMS among others.



- Application servers (Video servers, AVL server, databases, Device Management server, etc.)

PMR NB Network - Professional Mobile Narrowband network supporting TETRAPOL or TETRA standard and providing PMR voice services and Low data rate access to NB Mobile

LTE UE - HPM - High Power LTE Modem supporting basically 5W output power on the RF side and either USB or Ethernet interface on the host side- Main functions are LTE UE, configuration and management, security, troubleshooting and power management functions.- LTE UE-HPM integrates an internal RF duplexer which can be removed and replaced by an external one with enhanced/reduced performance according to the end configuration.

NB Mobile - NB terminal device supporting 10W or 3W RF output power according to supported PMR standard, either TETRAPOL or TETRA.

Vehicle Power Supply - Element providing appropriate power supply voltages to the vehicle system’s elements; at least, LTE UE- HPM and NB Mobile elements. Coexistence Box and System could be also supplied from the Vehicle Power Supply.

IP Clients and Apps - Generic actor using LTE UE – HPM for achieving specific operational missions- Client software and applications using IP-based protocols

PMR Coexistence Box - Complementary device used on the NB Mobile side to mitigate interferences between NB Mobile and LTE UE – HPM elements.

PMR Coexistence System - Complementary device used on the LTE UE – HPM side to mitigate interferences between NB Mobile and LTE UE – HPM elements.

Table 2: List of major system elements



Another view of this PMR Vehicle System is provided hereafter with additional information about interfaces.

ibd [Block] PMR Vehicle System [PMR Vehicle System]

IP Clients & Apps


«FlowPort» LTE RF

«block»PMR Coexistence System

«FlowPort» LTE RF

«FlowPort»NB Antenna

«block»PMR Coexistence Box


Switch_BB

Camera_IP_BB


optional

optional

NB RF

IP/Ethernet

Host I/F(IP/Ethernet)

IP/Ethernet

Power Supply

LTE RF_DL

LTERF_UL

Power Supply

Corr BB

Tx_Rx switching

Power Supply

Ref RF BB In

Power Supply

Ref RF NB

LTE RF_DL_diversity

Figure 21: PMR Vehicle System view

Except the PMR Coexistence System and the PMR Coexistence Box, all other elements of the Vehicle System do exist separately.The antenna system configuration, the coexistence elements but also the last filtering stage of the LTE UE-HPM will allow the full coexistence of the two narrowband and broadband systems.All those elements have to be considered.

3.3.2Physical hardware architectureThis section:

Identifies the hardware elements involved in the coexistence management on the NB and LTE UE – HPM sides

States the purpose of the different elements Shows the static relationship(s) of those elements



NB Mobile pathThe NB Mobile is an existing element of the NB system. Software and/or hardware modification can be done at baseband interface level only.NB-BB coexistence and NB performance/protection improvements can be achieved through the addition of a complementary element (external) on the NB Mobile side.This is the role of the PMR Coexistence Box.Since the NB Mobile is a HFDD device, switching between Tx and Rx operation shall be also considered at the coexistence box level.

An internal block diagram of the PMR Coexistence Box is illustrated in next figure with the different subsystem elements.

ibd [Block] PMR Coexistence Box [PMR Coexistence Box]

«FlowPort» Tx_RxSwitching

«block»RF switch 1



«block»RF Switch 2


«block»Low Band Filter

«block»High Band Filter

«block»Isolator

RF TxRF Tx

RF Rx/DMORF Rx/DMO

RF Tx

Figure 22 : Internal block diagram of the PMR Coexistence Box

The high level description of the different elements is provided in the next table.

Coexistence BoxSubsystem elements

Description

RF Switch 1, 2- RF switching stages used to switch between low band and high band filtering stages according to the UL and DL operations or Direct Mode Operation

Isolator- Isolation stage to limit reverse intermodulation effect (IMD3 & IMD5) when LTE UE – HPM is transmitting at the same time the NB Mobile is transmitting

Low Band Filter- RF bandstop filter used on the UL path to improve the transmitted wideband noise and spurious performance of the NB Mobile’s transmitter (inside DL band of LTE UE – HPM)

High Band Filter- RF bandstop filter used on the DL path to improve the blocking performance of the NB Mobile’s receiver (protection against UL signal coming from LTE UE – HPM)



Table 3: High level description of the different elements

The main static relationship between the Coexistence Box and the NB Mobile is illustrated in the previous diagrams (see flow ports).Five interfaces are required for the PMR Coexistence Box and described in next table. If the reference signal from the BB transmission is used, then a sixth interface is required.

External Interface Description

NB RF

RF interface between PMR Coexistence Box and NB mobile, combining Tx and Rx ports of the NB Mobile

- Type: I/O (SMA or TNC respectively for TETRA or TETRAPOL Mobile)- RF signal (TETRA/POL) input/output (Tx/Rx)- Ground

NB Antenna

RF interface between PMR Coexistence Box and NB RF antenna

- Type: I/O (SMA or TNC respectively for TETRA or TETRAPOL Mobile)- RF signal (TETRA/POL) from/to NB RF antenna- Ground

Coex Management

Switching signal from the NB Mobile (“Flow Port” Tx_Rx Switching)

- Type: Input- Hi/Lo logic signal- Ground

Power SupplyInterface to supply the Coexistence Box from the NB Mobile or Vehicle Power Supply with appropriate voltage for the RF switching stages

Ref RF NB Optional reference signal to LTE UE - HPM

Ref RF BBOptional reference signal corresponding to the BB transmitted signal from LTE UE-HPM. This signal is used only if Coexistence Box subtracts dynamically this reference signal from the NB received signal on DL.

Table 4: Interfaces for the PMR Coexistence Box

The Coexistence Box is part of the system elements to be specified and designed.



Detailed architecture and building block requirements of this Coexistence Box are provided in D3.1 document.

BB Mobile path (LTE UE – HPM)

The LTE UE - HPM is also an existing element of the BB system. But, at the contrary of the NB Mobile, the LTE UE – HPM can be modified from a hardware perspective to contribute with the PMR Coexistence System to the interference mitigation.NB-BB coexistence and BB performance/protection improvements can be achieved jointly through those two system elements.

A high level internal block diagram of the RF Front-End stage of the LTE UE-HPM is illustrated hereafter.

ibd [Block] RF [RF]

«FlowPort» Tx

«FlowPort» Rx

«FlowPort» Rx/Tx

Duplexer

«FlowPort» Tx

«FlowPort» Rx

«FlowPort» Rx/Tx

«FlowPort» Tx«FlowPort» Tx

Main Tx chain«FlowPort» Tx

«FlowPort» Tx

«FlowPort» Rx1«FlowPort» Rx1

Main Rx chain



Diversity Rx chain


«FlowPort» Clock

RF-BB I/F

«FlowPort» Tx

«FlowPort» Rx1

«FlowPort» Rx2

LTE Transceiv er

«FlowPort» Clock

RF-BB I/F

«FlowPort» Tx

«FlowPort» Rx1

«FlowPort» Rx2

«FlowPort» Clock

TCXO

«FlowPort» Clock

RF/Rx1

RF/Tx

Rx2_low

Rx1_low

RF Tx_low

Clock

Figure 23 : High level internal block diagram of the RF Front-End stage of the LTE UE-HPM

Performance and protection improvements for the LTE-UE shall be considered at the Duplexer level (duplexer performance can be optimized and easily replaced or moved inside the Coexistence System).PMR Coexistence Box is illustrated in next ibd figure with the different subsystem elements interacting with it.



ibd [Block] PMR Vehicle System [PMR Vehicle System]


«FlowPort» LTE RF

«block»PMR Coexistence System

«FlowPort» LTE RF


«block»PMR Coexistence Box



optional

NB RF

Power Supply

LTE RF_DL

LTERF_UL

Power Supply

Corr BB

Tx_Rx switching

Power Supply

Ref RF BB In

Power Supply

Ref RF NB

LTE RF_DL_diversity

Figure 24: PMR Coexistence Box

In this diagram, it is assumed that the original duplexer is removed from the LTE UE – HPM and a new duplexer with different characteristics is integrated inside the Coexistence System.3 separate antenna interfaces shall be considered on the LTE UE – HPM side.The foreseen interfaces from the PMR Coexistence System perspective are described in next table.


LTE RF_UL

RF interface between LTE UE – HPM device and PMR Coexistence System, supporting the Tx signal (UL) of the LTE UE – HPM device.This interface supports the corrected LTE RF signal (improved transmitted Tx noise performance) which is duplexed with the LTE RF_DL and transmitted to the antenna interface (at PMR Coexistence System’s output aka LTE RF)

- Type: Input (SMA)- RF signal (LTE Tx)- Ground

LTE RF_DL RF interface between PMR Coexistence System and LTE UE – HPM device, , supporting the main Rx signal (DL) of the LTE UE – HPM device.




- Type: Output (SMA)- RF signal (LTE Rx1)- Ground

LTE RF_DL_diversity

RF interface between PMR Coexistence System and LTE UE – HPM device, supporting the diversity Rx signal (DL) of the LTE UE – HPM device.

- Type: Output (SMA)- RF signal (LTE Rx2)- Ground

LTE RF

RF interface between PMR Coexistence System and LTE RF antenna.

- Type: Input/Output (SMA)- RF signal (LTE Tx & Rx1)- Ground

LTE RF_diversity

RF interface between PMR Coexistence System and LTE RF_diversity antenna

- Type: Input (SMA)- RF signal (LTE Rx2)- Ground

Ref RF BB In

Reference LTE Tx signal coming from the LTE RFIC

- Type: Input- Low power RF signal (LTE Tx) or base band signal- Ground

Corr BB

Compensation signal to be processed within LTE UE - HPM

- Type: Output- Digital signal (12-bit)

Power Supply Interface to supply the Coexistence System from the Vehicle Power Supply with appropriate voltage

Ref RF NB Optional reference signal coming from the NB Mobile- Type: Input- Low power RF signal (NB Tx)



External Interface Description- Ground

Ref RF BB

Optional reference signal corresponding to the transmitted BB signal- Type: Input- Low power RF signal (BB Tx)- Ground

Table 5: Foreseen interfaces from the PMR Coexistence System perspective

The Coexistence Box is part of the system elements to be specified and designed.Detailed architecture and building block requirements of this Coexistence Box are provided in D3.1 document.

3.4 HOMEDEVICE: Multimode Multi-standard Smart Home Device

3.4.1 RF Architecture description

The global considered architecture of the Home device is illustrated in the figure below, showing a home device architecture that contains various wireless systems aiming to offer multiple services and that can operate in different Regions and countries:

An internet gateway using the 3G/4G networks, operating in the 790~2700MHz band so as to be applicable to most of the countries.

A high-speed Wi-Fi connection based on the IEEE.802.11b/g/n standard. Here, even if widely used, the 5GHz WLAN band is deliberately not considered since this band is far from the others and thus is, to some extent, free of interferences.

Several home-automation and remote control services, operating in different frequency bands (2.4GHz, 868-MHz), with each using a specific standard (ZigBee, Bluetooth, Zwave or others).



Figure 25: Global architecture of a multimode multi-standard smart home device.

The figure below illustrates the Main PCB floor plan showing the physical position of the main RF functions embedded on the smart home device. Three kinds of sub-systems could be distinguished:

The intra-band systems which share the same frequency band The inter-band subsystems which operates in close frequency bands The MIMO system which need isolation between antennas

Figure 26: Smart Home device floor plan



For intra-band operation (same frequency band), the floor plan is defined first to get sufficient antenna isolation as defined in the D2.2 document.For inter-band operation ( close frequency bands) , the floor plan is optimized taken into account the contribution of both low cost discrete or off-the-shelf RF filters and antenna isolations. For MIMO systems the antenna isolation must meet the requirements described in D2.2 document. In order to get good simultaneous performances, dedicated combined solutions of antenna systems and filtering solutions allowing the coexistence of all the wireless systems will be explored.

More details of the global HOMEDEVICE RF architecture are given below:

Figure 27: Detailed Home device system architecture

The SOC (System On Package) built around the CPU (Central Processing Unit)is the heart of the home device driving all the RF sub-systems which are all able to work simultaneously.

The 3G/ 4G module allows to connect the home device to an external 3G/4G network.

The 11n 2.4G Wi-Fi sub-system allows to connect the home device to an external Wi-Fi Access Point (AP) and to get internet connection.

The BT sub-system allows to connect the home device to an external remote control, wireless audio system or wireless sensors..

The ZigBee sub-system allows to connect the home device to external Zigbee sensors.

The Zwave 868MHz RF sub-system to connect the home device to external Zwave 868MHz sensors.



3.4.2 Justification

This section deals with the justification of the proposed architecture.

3.4.2.1 Wi-Fi/LTE B7 In such a case (ie inter-band operation), the requested RF isolation is quite large because the operating frequency bands are very closed. This high value of RF isolation is due both to:

avoid saturation of the Wi-Fi receiver by the LTE B7 transmitter

avoid RF desensitization of the LTE B7 receiver by the OOB (Out Of Band) noise of the Wi-Fi transmitter

Due to the form factor of the home device platform, the RF isolation must be share between the embedded RF filters FL1 and FL2 and antenna isolations between LTE and WiFi systems. Off-the-shelf low cost low lost FL1& FL2 BAW filter are chosen in order to minimize requested additional antenna RF isolation. The rejection of this filter in LTE B7 TX band [2500-2570MHz] is greater than 40dB while the losses in the Wi-Fi 2.4G band are close to 2dB. Taken into account the global isolation requirement of 60dB (defined in D2.2), the antenna isolation contribution in B7 TX band must be then at least 20dB. The design of the corresponding antenna system is shown in D3.1 document.

3.4.2.2868MHz/LTE B20 In such a case (ie inter-band operation), the requested RF isolation is also quite large because the operating frequency bands are very closed. As in the previous case, this high value of RF isolation is due both to:

avoid saturation of the 868MHz receiver by the LTE B20 transmitter

avoid RF desensitization of the LTE B20 receiver by the OOB (Out Of Band) noise of the Wi-Fi transmitter

Due to the form factor of the home device platform, the RF isolation must be also share between the embedded RF filters FL3 and antenna isolations between 868MHz and LTE B20 systems. Off-the-shelf low cost low lost RF filter are chosen in order to minimize requested additional antenna RF isolation. The rejection of this filter in LTE 20 TX band [832-862MHz] is greater than 25dB while the losses in the Wi-Fi 2.4G band are close to 2dB. Taken into account the global isolation requirement of 40dB (defined in D2.2), the antenna isolation contribution in B7 TX band must be then at least 15dB. The design of the corresponding antenna system is shown in D3.1 document.

3.4.2.3WiFI/BT



In such a case (ie intra-band operation), the requested RF isolation is quite large because the systems operates in the same frequency band. This high value of RF isolation is due both to:

avoid perturbation of each sub-system

Due to the form factor of the home device platform, the RF isolation (ie antenna isolation) must be maximized by

physical separation optimized antenna design

Taken into account the RF isolation requirement of 25dB (defined in D2.2), the antenna isolation contribution 25dB. The design of the corresponding antenna system is shown in D3.1 document.

3.4.2.4WiFI/ZigBee

In such a case (ie intra-band operation), the requested RF isolation is quite large because the systems operates in the same frequency band. This high value of RF isolation is due both to:

avoid perturbation of each sub-system

Due to the form factor of the home device platform, the RF isolation (ie antenna isolation) must be maximized by

physical separation optimized antenna design

Taken into account the RF isolation requirement of 25dB (defined in D2.2), the antenna isolation contribution 25dB. The design of the corresponding antenna system is shown in D3.1 document.

The table below summarizes the requested filters and antenna isolations

Systems Antenna Isolation (dB)LTE vs. Wi-Fi > 20

(assuming 40dB isolation provided by a filter)Wi-Fi vs. ZigBee > 25Wi-Fi vs. Bluetooth > 25Zwave (868MHz) vs. LTE band 20 (800MHz) > 25

(assuming 15dB isolation provided by a filter)

Table 6: Summarized antenna isolation requirements



4 Measurement techniques : Coexistence of cellular, wireless and broadcasting networks

4.1.1 Cellular and WLAN Rising density of wireless networks and related rising number of user equipment increase the vulnerability of the interference generation. These interfering signals could be generated as the result of coexistence of wireless standards like Long-Term Evolution (LTE), High Speed Packet Access (HSPA), Wideband Code Division Multiple Access (WCDMA), Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Wireless Fidelity (Wi-Fi) and other services transmitted in adjacent bands of radio spectrum (e.g. ZigBee, Bluetooth) [1], [2]. For exploring, measuring and evaluating the interaction of possible coexistence scenarios between cellular and WLAN systems (mainly intermodulation problems), an appropriate measurement workplace is needed. General block diagram of such measurement workplace is shown in Fig. 28 a) and b).

a) Real World environment

b) Laboratory conditions



Figure 28 : Proposed general block diagram of workplace for measuring the interaction between 2G and 3G wireless networks in a) real World environment and in b) laboratory conditions.

There are proposed two measurement workplaces for the exploring of the coexistence between different wireless networks. The radio frequency (RF) signals can be real received (see Fig. 28 a)) or synthetically generated (see Fig. 28 b)). Real RF signals (from 2G and 3G networks) are acquired by common receiving equipment (antennas, low noise amplifiers). In the second case, multimedia services can be generated synthetically by advanced laboratory devices from Rohde & Schwarz (R&S). Essentially, both configurations can be divided into two main parts. The first one represents the input signals. The second one is the measurement side, where the impact of coexistences on performances for chosen type of multimedia systems can be analysed. The proposed measurement workplace is appropriate for exploring the vulnerability of the 2G and 3G networks to interferences from their coexistences. Furthermore, both proposed measurement workplaces can be used together (hybrid). It means that it is possible to explore the coexistence between cellular services from real environment and WLAN services, generated in laboratory conditions, and vice versa.

The main parameters of 2G/3G network which shall be observed are follows: User Data Rate [Kb/s] - describing throughput of user data Control Data Rate [Kb/s] - describing throughput of control data MAC Data Rate [Kb/s] - describing throughput of MAC layer CQI [-] - is Channel Quality Indicator EVM [%] – is Error Vector Magnitude.

4.1.2 Cellular and DVB Nowadays, the demand for multimedia services (video, audio, image and data) in high quality is rapidly increasing. The Digital Video Broadcasting – Terrestrial/Handheld (DVB-T/H) standard, its second generation version (DVB-T2) and the LTE standard are the most promising systems to fulfil demand on advanced multimedia services (e.g. high definition image and video quality), especially in Europe. However, LTE mobile system can operate in a part of the UHF band, allocated to DVB-T/T2 TV services in the past. Consequently, DVB-T/T2 and LTE services can occupy either the same or adjacent frequency spectrum. As a result, unwanted coexistence can occur between DVB-T/T2 and LTE services [1], [2].For exploring, measuring and evaluating the interaction of possible coexistence scenarios between DVB-T/H/T2/T2-Lite and LTE RF signals, an appropriate measurement workplace is needed. General block diagram of such measurement workplace is shown in Fig. 29 a) and b).




b) Laboratory conditionsFigure 29: Proposed general block diagram of workplace for measuring the interaction between different DVB services and LTE networks in a) real World environment and in b) laboratory conditions ([3], [6]).

There are proposed two measurement workplaces for the exploring of the coexistence between LTE and DVB-T/T2 systems. The RF signals can be real received (see Fig. 29 a)) or synthetically generated (see Fig. 29 b)). Real RF signals (from LTE eNodeB and DVB-T/T2 Single Frequency Network (SFN)) are acquired by common receiving equipment (antennas, low noise amplifiers). In the second case, LTE mobile and digital TV (DTV) services can be generated synthetically by advanced laboratory devices from Rohde & Schwarz (R&S). Essentially, both configurations can be divided into two main parts. The first one represents the input signals. The second one is the measurement side, where the impact of coexistences on performances for chosen type of multimedia systems can be analysed. The proposed measurement workplace is appropriate for exploring the vulnerability of the LTE and DVB-T/T2 networks to interferences from their coexistences. Furthermore, both proposed measurement workplaces can be used together (hybrid). It means that it is possible to explore the coexistence between services,



provided from real LTE eNodeB and DVB-T/H/T2/T2-Lite services, generated in laboratory conditions, and vice versa [3]-[7].

The main parameters of DVB-T/H services which shall be observed are follows: Bit Error Ratio before Viterbi decoding (BER) – raw errors (in channel) Bit Error Ratio after Viterbi decoding (BER) – after FEC decoding Modulation Error Ratio (MER) [dB].

The main parameters of DVB-T2/T2-Lite services which shall be observed are follows:

Bit Error Ratio before LDPC decoding (BER) – raw errors (in channel) Bit Error Ratio after LDPC decoding (BER) – after FEC decoding Modulation Error Ratio (MER) [dB] Number of needed decoding iterations [-].

The main parameters of LTE services which shall be observed are follows: User Data Rate [Kb/s] - describing throughput of user data Control Data Rate [Kb/s] - describing throughput of control data CQI [-] - is Channel Quality Indicator EVM [%] – is Error Vector Magnitude.

4.1.3 Cellular and DVB with CR supportIn recent decade, significant attention is being dedicated to TV White Spaces (TVWS) which can resolve the interference problem through cognitive radio (CR) technology in the coexistence scenarios [8], [9]. On the other hand, possible interference may occur when narrowband systems (e.g. DTV) are operating under severe environmental conditions. Hence, a possible negative impact of the LTE system (downlink and uplink), using CR technology (marked as LTE-CR) on DVB-T/T2 services should be explored [1], [2]. For this purpose a previously proposed and presented measurement workplace can be used (see Fig. 29). Furthermore, for both systems, the same parameters should be monitored and measured.

4.1.4 ZigBee vs Wi-FiThe number of wirelessly connected multimedia devices and different communication standards, supported by these devices, is rapidly increasing. However, the appropriate frequency bands (licensed and unlicensed) for data transmission by these standards are very limited. The rising density of wireless networks and their coexistence in the same or adjacent radio frequency (RF) spectrum can significantly decrease the quality of provided services. Such coexistence can be occurred between ZigBee (IEEE 802.15.4) and Wi-Fi networks (including the IEEE 802.11b/g/n standards), which operate in the unlicensed Industrial, Scientific and Medical (ISM) band at 2.4 GHz [1], [2].For exploring, measuring and evaluating the interaction of the coexistence between ZigBee and W-Fi RF signals in ISM band, an appropriate measurement workplace is



needed. General block diagram of such measurement workplace is shown in Fig. 30 a) and b).



Figure 30: General block diagram of proposed workplace for measurements of the interaction between ZigBee (IEEE 802.15.4) and the IEEE 802.11b/g/n networks in a) real World environment and in b) laboratory conditions (based on [10]).

There are proposed two measurement workplaces for the exploring of the coexistence between ZigBee (IEEE 802.15.4) and Wi-Fi (IEEE 802.11b/g/n) systems. The RF signals can be real received (see Fig. 30 a)) or synthetically generated (see Fig. 30 b)). Real RF signals (from Wi-Fi and ZigBee systems) are acquired by common receiving equipment (antennas, low noise amplifiers). In the second case, multimedia services can be generated synthetically by advanced laboratory devices from Rohde & Schwarz (R&S).The proposed measurement workplace is appropriate for exploring the vulnerability of the ZigBee and Wi-Fi networks to interferences from their coexistences.



The main parameters of ZigBee services which shall be observed are follows: Power level of the RF signal Bit Error Ratio (BER) – raw errors (in channel) EVM [%] – is Error Vector Magnitude.

The main parameters of Wi-Fi services which shall be observed are follows: Power level of the RF signal Bit Error Ratio (BER) – raw errors (in channel) EVM [%] – is Error Vector Magnitude.

4.1.5 Bluetooth Low Energy (BLE) and Wi-Fi

Bluetooth Low Energy (BLE) (sometimes marked as Bluetooth Smart) is a wireless personal area (WPA) network technology designed by the Bluetooth Special Interest Group. It has been developed for wireless communication purposes in the health-care, security and home entertainment environments. Compared to classic Bluetooth, BLE provides ultra-low power consumption with possibility to use a stand-ard coin-cell battery for few years run of device and lower implementations cost. It uses the adaptive frequency hopping (FH) to minimize interference from other tech-nologies in the 2.4 GHz ISM Band. However, as it is in the case of ZigBee and Wi-Fi, possible coexistence scenarios also can occur in this case.

For exploring and measurement of such coexistence a previously proposed and presented measurement workplace can be used (see Fig. 31). Of course, instead of ZigBee system a BLE system is used. Due to limited performances of R&S FSQ de-modulator (not able to synchronized FH signal), evaluation of BLE signal will be per-formed by post-processing using signal acquisition unit.





Figure 31 : General block diagram of proposed workplace for measurements of the interaction between BLE (Bluetooth v. 4.1) and the IEEE 802.11b/g/n networks in a) real World environment and in b) laboratory conditions.

There are proposed two measurement workplaces for the exploring of the coexistence between BLE (Bluetooth v. 4.1) and Wi-Fi (IEEE 802.11b/g/n) systems. The RF signals can be real received (see Fig. 31 a)) or synthetically generated (see Fig. 31 b)). Real RF signals (from Wi-Fi and BLE systems) are acquired by common receiving equipment (antennas, low noise amplifiers). In the second case, multimedia services can be generated synthetically by advanced laboratory devices from Rohde & Schwarz (R&S).The proposed measurement workplace is appropriate for exploring the vulnerability of the BLE and Wi-Fi networks to interferences from their coexistences.

The main parameters of BLE services which shall be observed are follows: Power level of the RF signal Bit Error Ratio (BER) – raw errors (in channel).

The main parameters of Wi-Fi services which shall be observed are follows: Power level of the RF signal Bit Error Ratio (BER) – raw errors (in channel) EVM [%] – is Error Vector Magnitude.



5 Conclusions

Architectures of the coexistence techniques, coordination and recommendations for system integrators have been explored and are shown in this document, covering different applications and technologies. The aim is to bring innovating solutions for the design of future wireless systems and devices minimizing the impact of interferences and coexisting properly all together.



6 References

[1] CORTIF deliverable, D2.2: Report on “Use case and requirements”.[2] CORTIF deliverable, D2.3: Report on “System architecture”.[3] L. POLAK et. al. LTE: Mobile Communication Networks and Digital Television

Broadcasting Systems in the Same Frequency Bands – Advanced Co-Existence Scenarios. Radioengineering, 2014, vol. 23, no. 1, pp. 375-386.

[4] ITU-R BT.2035 (2003). Guidelines and techniques for the evaluation of digital terrestrial television broadcasting systems. Report ITU-R, BT Series.

[5] ITU-R BT.1368-10 (2003). Planning criteria, including protection ratios, for digital terrestrial television services in the VHF/UHF bands. Recommendation ITU-R, BT Series.

[6] ITU-R BT.2265 (2012). Guidelines for the assessment of interference into the broadcasting service. Report ITU-R, BT Series.

[7] ITU-R BT.2241 (2011). Compatibility studies in relation to Resolution 224 in the bands 698-806 MHz and 790-862 MHz. Report ITU-R, M Series.

[8] C. S. SUM and et. al. Cognitive Communication in TV White Spaces: An Overview of Regulations, Standards, and Technology,” IEEE Communications Magazine, 2013, vol. 51, no. 7, pp. 138–145.

[9] K. HEEJOONG and et. al. Comparison on DTV Affected Range by Difference of Secondary User Bandwidth in Adjacent Channel (Focused on Narrowband System for DTV White Space), in Proceedings book of the 9th International Symposium ISWCS. (Paris, France), pp. 28–31, August 2012.

[10] J. NEBURKA and et. al. Study of the Coexistence between ZigBee and Wi-Fi IEEE 802.11b/ g Networks in the ISM Band, in Proceedings of the 25th International Conference Radioelektornika 2015. (Pardubice, Ceech Republic), pp. 106–109, April 2015.



7 List of Abbreviations

ATVSO Analogue TV Switch Off

AP Access Point

BB Broad Band

BLE Bluetooth Low Energy

BT Bluetooth

CR Cognitive Radio

CORTIF Coexistence Of RF Transmissions In the Future

CPU Central Processing Unit

DL Down Link

DVB Digital Video Broadcast

DVB T-H Digital Video Broadcast Terrestrial-Handheld

ECC Envelop Correlation Coefficient

FEC Forward Error Correction

FDD Frequency Division Duplexing

FH Frequency Hopping

GHz Gigahertz

GSM Global System for Mobile Communications

HPM High Power Modem

HSPA High Speed Packet Access

ISM Industrial, Scientific and Medical (RF Bands)

IMD3 -5 Inter Modulation Distorsion 3 -5 order

LTE Long Term Evolution

MHz Megahertz



MIMO Multiple Input Multiple Output

NAS Network Attached Storage

NB Narrow Band

PCB Printed Circuit board

PMR Professional Mobile Radio

PU Primary User

QoS Quality of Service

STB Set Top Box

SISO Single Input Single Output

SU Secondary User

TDD Time Division Duplexing

UL Uplink

RF Radio Frequency

TVWS TV White Space

UE User End

UTM S Universal Mobile Telecommunications System

WCDMA Wideband Code Division Multiple Access

WiFi Wireless Fidelity

WiMax Worldwide Interoperability for Microwave Access

WPA Wireless Personal Area

WRC World Radio Conference

WSN Wireless Sensor Network

WP Work Package


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