1、 Rep. ITU-R M.2030 1 REPORT ITU-R M.2030 Coexistence between IMT-2000 time division duplex and frequency division duplex terrestrial radio interface technologies around 2 600 MHz operating in adjacent bands and in the same geographical area (Question ITU-R 229/8) (2003) 1 Introduction 1.1 Introducti
2、on and outline In this Report the coexistence between IMT-2000 time division duplex (TDD) and frequency division duplex (FDD) radio interfaces are investigated. Specifically, the interference properties between IMT-2000 CDMA Direct Spread (also called WCDMA or UTRA FDD) and IMT-2000 CDMA TTD (also c
3、alled UTRA TDD) with its two modes high chip rate (HCR, 3.84 Mchip/s) TDD and low chip rate (LCR, 1.28 Mchip/s) TDD are studied for a large number of scenarios. The main part of the Report describes base station to base station (BS-BS) interference for both proximity and co-location scenarios. Also
4、mobile station (MS) to BS, BS-MS and MS-MS scenarios are studied for proximity scenarios. In 2.4-2.5, the transmitter and receiver characteristics are described. In 2.8 the relation between the external interference level, and coverage and capacity is discussed. In 3.2 the methodology of the determi
5、nistic BS-BS and MS-MS scenarios is described. The Monte Carlo methods are described in 3.3. The results are presented in 4 and conclusions are made in 5. An overview of the results can be obtained by reading 1, 2.1-2.3 and 5. 1.2 Scope For the purposes of the analysis in this Report it has been ass
6、umed that TDD and FDD systems at 2.5 GHz will have similar characteristics to those of WCDMA and HCR/LCR TDD as given in Recommendation ITU-R M.1457. 1.3 Summary This Report provides an analysis and present results of the consequences of adjacent channel interference (ACI) on FDD and TDD compatibili
7、ty for a number of scenarios. This study is based on deterministic calculations for BS-BS scenarios leading to required separation distance and/or isolation requirements or supported cell range. The interference from MSs into MSs and BSs is analysed both with deterministic and statistical calculatio
8、ns leading to capacity loss and/or probability of interference. 2 Rep. ITU-R M.2030 The feasibility of certain scenarios is subject to a trade-off between technical, regulatory and economical factors. In this Report, different points of view have been reflected on factors such as propagation conditi
9、ons, user density and placement, which correspond to different trade-off choices. The above views by no means exclude other points of views. The conclusions below reflect only the studies made in this Report. It is recognized that any potential improvement brought about by mitigation techniques such
10、 as site engineering, adaptive antenna, etc, is not covered in this Report and should be the subject of further study. Main results BS-BS interference: General observations Several scenarios and parameter settings examined are associated with severe interference problems. The separation distances ha
11、ve been calculated over an interval of tolerated external interference where the smaller value for separation distance implies high levels of planned tolerated external interference which in turn implies smaller coverage and/or capacity and higher transmit powers for the MS in the victim system. The
12、re is no fundamental difference in magnitude of interference when considering FDD downlink (DL) to TDD uplink (UL) interference or when considering TDD DL to FDD UL for any of the examined scenarios. Thus, the potential problems come from the basic fact that DL transmitters are geographically and sp
13、ectrally close to sensitive UL receivers, regardless of the duplex method involved. Minimum requirements available in third generation partnership project (3GPP) specifications on transmitter and receiver characteristics are assumed to the maximum extent possible. It could be noted that practical eq
14、uipment may be better than required in the specifications. For several scenarios large values of separation distances or additional isolation are needed to obtain low interference conditions. Some scenarios have low separation distances and do not require additional isolation. In some deployment sce
15、narios separation distances or filtering requirements can be traded off against coverage and higher MS transmit powers in the victim system. There are a number of basic actions that can be taken alone or in combination in order to combat the BS-BS interference problems. All actions are associated wi
16、th some kind of cost or other difficulties that must be taken into account as well, as there is always a trade-off to consider. BS-BS interference in proximity: WCDMA/3.84 Mchip/s TDD The required separation distances are in a range from 1 m to 15 km depending upon the cell types involved and carrie
17、r separation used. They are the lowest for pico-to-pico scenarios and the highest for macro-to-macro scenarios. Rep. ITU-R M.2030 3 BS-BS interference in proximity: WCDMA/1.28 Mchip/s TDD Based on assumptions for reference separation distances, only the macro-to-macro scenario requires significant a
18、dditional isolation. For other scenarios, the basic isolation is sufficient. BS-BS co-location: WCDMA/3.84 Mchip/s Co-location of BSs will be prevalent in future systems When WCDMA and 3.84 Mchip/s macro BSs are co-located the noise floor of both systems are impacted considerably when considering a
19、30 dB coupling loss Coverage and capacity will be severely affected, if appropriate isolation is not provided between the BSs. Based on the existing specifications and minimum coupling loss (MCL) assumptions, even a guardband of 5 MHz and 10 MHz will not remove the problem. Continued studies must de
20、fine needed system specifications and guardbands, as appropriate, considering BS co-location, taking into consideration the fact that some degree of isolation may be achieved in practical systems. MS-BS, BS-MS interference For the studied Manhattan scenarios with uniformly distributed outdoor-only u
21、sers, Monte Carlo simulations suggest that MS-BS, BS-MS interference will have a small or negligible impact on the capacity when averaged over the system. MS-MS interference The Monte Carlo simulations suggest that MS-MS interference will have a small or negligible impact on the capacity when averag
22、ed over the system and using uniform user densities (see 4.2.2.3). Deterministic MS-MS calculations suggest that one mobile might create severe interference to another geographically and spectrally close mobile (see 4.2.3). Studies are therefore needed where non-uniform user densities are considered
23、, which are more realistic in real systems in hot spot areas (see 4.2.3). The outage cannot be reduced much even at the cost of BS density or capacity decrease. Instead, the requirements should be set on the service level. 2 Assumptions 2.1 Radio interface technologies considered In this Report the
24、IMT-2000 technologies considered are the FDD based IMT-2000 CDMA Direct Spread radio specification and the TDD based IMT-2000 CDMA TDD with its two modes HCR TDD (3.84 Mchip/s) and LCR TDD (also known as TD-SCDMA, 1.28 Mchip/s). They are for simplicity referred to as FDD and TDD, respectively, in th
25、e appropriate sequence. 4 Rep. ITU-R M.2030 2.2 Interference scenarios This Report considers the following basic scenarios: Interference to FDD BS caused by TDD BS (Deterministic calculations) Interference to TDD BS caused by FDD BS (Deterministic calculations) Interference to FDD BS caused by TDD u
26、ser equipment (UE) (Monte Carlo simulations) Interference to TDD BS caused by FDD UE (Monte Carlo simulations) Interference to FDD UE caused by TDD UE (Monte Carlo simulations) Interference to TDD UE caused by FDD UE (Monte Carlo simulations) Interference to FDD UE caused by TDD BS (Monte Carlo simu
27、lations) Interference to TDD UE caused by FDD BS (Monte Carlo simulations) Interference to FDD UE caused by TDD UE (Deterministic calculations) Interference to TDD UE caused by FDD UE (Deterministic calculations) The methodology used in the calculations and simulations is described in 3. 2.3 Involve
28、d cell layers All scenarios should be considered, i.e. macro, micro and pico. However, not all combinations of FDD and TDD cell layers have been investigated since some are considered less likely. 2.3.1 Frequency allocation The study focuses on coexistence in the IMT-2000 band between 2 500 MHz and
29、2 690 MHz. A principle allocation according to Fig. 1 is assumed. This study focuses on interference between TDD and FDD UL as well as TDD and FDD DL. Interference between FDD UL and FDD DL is not considered (because of the frequency separation). No particular assumptions on the sizes of the bands h
30、ave been made since the focus is on the border effects between FDD UL and TDD, and TDD and FDD DL, respectively. Rap 2030-012 500 2 690Frequency (MHz)FIGURE 1Assumed frequency allocationFDD UL TDD FDD DLIt is assumed in the calculations that the TDD and FDD bands are separated with a certain amount
31、of bandwidth (possibly of zero width). The carrier separation is defined as the spectral distance between the centre frequencies of the respective bands, including possible guardbands. Rep. ITU-R M.2030 5 Rap 2030-02System 1 System 2Carrier separationFIGURE 2Carrier separationThe carrier separation
32、thus consists of half the bandwidth of system 1 plus half the bandwidth of system 2 plus possibly extra guardband. For WCDMA 3.84 Mchip/s TDD the carrier separation is a minimum 2.5 + 2.5 = 5 MHz and for WCDMA/TD-SCDMA it is minimum 2.5 + 0.8 = 3.3 MHz. With 5 MHz extra guardband the carrier separat
33、ion thus becomes 10 or 8.3 MHz, respectively. 2.3.2 Deployment scenarios and BS position In this study, different types of BSs (for both FDD and TDD deployment) are considered (macro, micro and pico). A macro BS is assumed to be located above rooftop and to be deployed in areas with both high and lo
34、w user densities. The main objective of the macro BSs is to achieve coverage over a relatively large area. A micro BS is assumed to be located outside below rooftop and are deployed in areas with high user densities. The micro BSs are mainly used to enhance the capacity in areas with high user densi
35、ties. The pico BS is located indoors and used for indoor coverage only. Typical deployment scenarios are in an office building. The pico BS could in principle be located at any floor within a building. However, it is here assumed that the height of the pico BS is approximately the same as the height
36、 of a micro BS. The assumed heights of the different BSs are summarized in Table 1. Furthermore, the average building height is assumed to be 24 m and thus, the macro BSs are positioned 6 m above the average rooftop. TABLE 1 Assumed heights of the macro, the micro and the pico BS (both FDD and TDD)
37、BS type Height (m) Macro 30 Micro 6 Pico 6 6 Rep. ITU-R M.2030 2.4 Transmitter characteristics The transmitter characteristic includes output power restrictions and transmitter antenna gain. 2.4.1 Output power and antenna gain The BS maximum output power and antenna gain for FDD and TDD BSs are foun
38、d in Table 2. TABLE 2 Maximum output power and Tx antenna gain for the macro, micro and pico BSs (FDD and TDD) The FDD BS is assumed to transmit continuously whereas the TDD BS is assumed to transmit half of the time (activity factor = 0.5). The FDD and TDD MS maximum output power and transmission a
39、ntenna gain are found in Table 3. TABLE 3 Maximum output power and Tx antenna gain for FDD and TDD MSs BS type Maximum output power (dBm) Antenna gain (Tx) (dBi) FDD macro 43 15 FDD micro 30 6 FDD pico 24 0 3.84 Mchip/s TDD macro 43 15 3.84 Mchip/s TDD micro 30 6 3.84 Mchip/s TDD pico 24 0 TD-SCDMA
40、macro 34(1)15 TD-SCDMA micro 21(1)6 TD-SCDMA pico 12(1)3(1)(1)The transmitter power of TD-SCDMA BS is assumed lower than for 3.84 Mchip/s because of the use of 8-element smart antenna system employed for TD-SCDMA. MS type Maximum output power (dBm) Antenna gain (Tx) (dBi) FDD 21 0 TDD 21 Rep. ITU-R
41、M.2030 7 2.4.2 Spectrum masks and adjacent channel leakage ratio (ACLR) values The BS ACLR values in Table 4 are from 1 and 2 respectively. For the TDD BS, the ACLR requirement refers to the case of coexistence with other (TDD or FDD) systems. The below values are valid for 3.84 Mchip/s TDD. For 1.2
42、8 Mchip/s TDD, see 2.6. TABLE 4 FDD and TDD BS ACLR The ACLR values employed for FDD and TDD MSs can be found in Table 5. The values are taken from 3 and 4 except for 15 MHz where an assumption has been made. TABLE 5 FDD and TDD MS ACLR 2.5 Receiver characteristics 2.5.1 Receiver noise floor and ant
43、enna gain (FDD and TDD) A noise floor of 103 dBm and 99 dBm supposes a noise figure (NF) of 5 and 9 dB respectively (thermal noise power 174 dBm/Hz 3.84 MHz = 108 dBm/3.84 MHz). The receiver noise floor and the receiver antenna gain for FDD and TDD BSs are found in Table 6. The corresponding values
44、for the FDD and TDD MSs are found in Table 7. Carrier separation (MHz) FDD BS ACLR (dB) TDD BS ACLR (dB) 5 45 70 10 50 70 15 67 70 Carrier separation (MHz) FDD MS ACLR (dB) TDD MS ACLR (dB) 5 33 33 10 43 43 8 Rep. ITU-R M.2030 TABLE 6 FDD and TDD BS receiver noise floor and antenna gain TABLE 7 FDD
45、and TDD MS receiver noise floor and antenna gain 2.5.2 Receiver sensitivity The BS reference sensitivity levels in Table 8 (specified for a 12.2 kbit/s service, BER must not exceed 0.001) are taken from 1 and 2. TABLE 8 BS reference sensitivity for FDD and TDD BSs BS type Receiver noise floor (dBm)
46、Antenna gain (Rx) (dBi) FDD macro 103 15 FDD micro 103 6 FDD pico 103 0 TDD macro 103 15 TDD micro 103 6 TDD pico 103 0 MS type Receiver noise floor (dBm) Antenna gain (Rx) (dBi) FDD 99 0 TDD 99 0 BS type BS reference sensitivity level (dBm) FDD macro 121 FDD micro 121 FDD pico 121 3.84 Mchip/s TDD
47、macro 109 3.84 Mchip/s TDD micro 109 3.84 Mchip/s TDD pico 109 Rep. ITU-R M.2030 9 The MS receiver sensitivity values presented in Table 9 are from 3 and 4, respectively. TABLE 9 FDD and TDD MS receiver sensitivity 2.5.3 Adjacent channel selectivity (ACS) specifications The BS ACS values in Table 10
48、 are (indirectly derived) from 1 and 2 except for 15 MHz where an assumption has been made. Furthermore, the FDD and TDD MS ACS are found in Table 11. The below values are valid for 3.84 Mchip/s TDD. For 1.28 Mchip/s TDD, see 2.6. TABLE 10 FDD and TDD BS ACS TABLE 11 FDD and TDD MS ACS 2.6 Resulting
49、 adjacent channel interference ratios (ACIRs) The ACS and ACLRs have been taken from the 3GPP specifications for 5 and 10 MHz carrier separation and have been estimated for 15 MHz carrier separation. MS type BS reference sensitivity level (dBm) FDD 117 TDD 105 Carrier separation (MHz) FDD BS ACS (dB) TDD BS ACS (dB) 5 46 46 10 58 58 15 66 66 Carrier separation (MHz) FDD MS ACS (dB) TDD MS ACS (dB) 5 33 33 10 43 43 10 Rep. ITU-R M.2030 The above ACLR and ACS values result
