In this paper, we will study the scheme of Single-Frequency Dual-Cell HSDPA (SF-DC HSDPA) which is introduced to simultaneously transmit two separate packet streams from two cells to a mobile. The inter-stream interference is suppressed by the linear-MMSE equalizer at the mobile. In the simple implementation studied in this paper, the schedulers at the two cells are independent without information exchange. Our study is based on both analysis and simulations. SF-DC HSDPA offers significantly higher data rates to users in the handover region. It also achieves dynamic load balancing in terms of resource utilizations across cells. Furthermore, all these gains can be obtained without degrading the performance of users not in handover and the legacy users. The gain from SF-DC is particularly substantial for users in heavily loaded cells surrounded by lightly loaded neighboring cells. In addition, such gain can increase with loading at a given loading ratio between the heavily loaded and lightly loaded cells. SF-DC is easy to implement with only incremental complexity to the current mobile and network equipment.

In this paper, we analyze the capacity of Circuit Switched Voice over High Speed Packet Access (HSPA) (CSoHS), using a Release 7 HSPA system that supports Continuous Packet Connectivity (CPC). On the Downlink (DL), we modeled the power consumption of the Fractional Dedicated Physical Channel (F-DPCH) and the Enhanced DCH Hybrid ARQ Indicator Channel (E-HICH). On the uplink (UL), we modeled the overhead channels, High Speed Dedicated Physical Control Channel (HS-DPCCH) and Enhanced DCH Dedicated Physical Control Channel (E-DPCCH). Our results show voice capacity gains that are achievable with CPC. We also show the gains in downlink voice capacity that are achievable by using the MAC-segmentation feature, introduced in Release 7.

Multiple Input Multiple Output (MIMO) transmission improves downlink spectral efficiency and is a key feature of Release 7 High Speed Downlink Packet Access (HSDPA). When the Node-B is configured in the MIMO mode with secondary common control pilot channel (S-CPICH), the power amplifiers (PAs) for the two transmit antennas are not balanced. A common pre-coder is required to balance the PAs for legacy and dual-stream MIMO transmissions. In addition, codebook restriction is needed to balance the PAs for single-stream MIMO transmissions. Despite codebook restriction, MIMO performance degradation is small. Legacy user performance in a MIMO cell suffers due to power and interference penalties associated with the Secondary Common Pilot Channel (S-CPICH). By reducing the S-CPICH transmit power, this degradation can be reduced, without significantly compromising the channel estimation quality for MIMO users in the cell.

Higher Order Modulation (HOM, 64-QAM) and Multiple Input Multiple Output (MIMO) transmissions are two key features introduced in the Release 7 (HSPA+) WCDMA systems to improve downlink performance. This paper focuses on the performance analysis of 64-QAM and MIMO in the WCDMA system. We describe the equalizer design for supporting these features as well as the simulation results demonstrating the higher system throughput and better user experience provided by these features.

The newly standardized Dual-Carrier HSDPA offers two-carrier aggregation on the downlink. In this paper, we investigate the performance gains from the dual-carrier operations with both full buffer and bursty traffic models. With full buffer traffic, dual-carrier offers dynamic load balancing and increase in user data rate, system capacity and spectral efficiency. All the users throughout the system enjoy the data rate increase. With bursty traffic, dual-carrier provides substantial gain in user experience measured by burst rates or latency under all loading conditions. Moreover, the gain with bursty traffic is universal not only for all the users but also for a very wide range of scheduling algorithms. Our results are based on analysis and extensive simulations. Design issues are also addressed in this paper.

A great deal of attention has been devoted in the recent literature to the study of the bit-error rate (BER) performance of phase-shift keyed (PSK) constellations, due to their high spectral efficiency. It is well known that an error in phase or timing synchronization affects the probability of correct decisions at the receiver. This problem becomes much more significant as data rates increase, and the corresponding symbol durations decrease. In this letter, we look into this problem and analyze the exact BER performance of generalized hierarchical PSK constellations under imperfect phase or timing synchronization over additive white Gaussian noise channels.

When the number of bits per symbol is odd, the peak and average power of transmission can be reduced by using cross quadrature amplitude modulations (QAMs) instead of rectangular QAMs. However, since perfect Gray coding is not possible for cross QAMs, using Smith-style Gray coding, this paper derives the exact bit error rate (BER) for cross QAM constellations over additive white Gaussian noise (AWGN) and Rayleigh fading channels.

We derive an explicit closed-form expression for the exact bit-error rate (BER) computation of generalized hierarchical M-ary pulse amplitude modulations over additive white Gaussian noise (AWGN) and fading channels. This expression can also be used to obtain the exact BER of generalized hierarchical quadrature amplitude modulations (square and rectangular). For the AWGN case, these expressions are in the form of a weighted sum of complementary error functions, and are solely dependent on the constellation size M, the carrier-to-noise ratio, and a constellation parameter which controls the relative message importance.

We obtain in this paper generic expressions in M for the exact bit-error rate of the generalized hierarchical 2/4//spl middot//spl middot//spl middot//M-phase-shift keyed constellations over additive white Gaussian noise (AWGN) and fading channels. For the AWGN case, these expressions are in the form of a weighted sum of Pawula F-functions and are solely dependent on the constellation size M, the carrier-to-noise ratio, and a constellation parameter which controls the relative message importance. The mathematical expressions are illustrated with some select numerical examples.

Hierarchical constellations offer a different degree of protection to the transmitted messages according to their relative importance. As such, they find interesting application in digital video broadcasting systems as well as wireless multimedia services. Although a great deal of attention has been devoted in the literature to the study of the bit error rate (BER) performance of uniform quadrature amplitude modulation (QAM) constellations, very few results were published on the BER performance of hierarchical QAM constellations. We obtain exact and generic expressions in M for the BER of the generalized hierarchical M-PAM (pulse amplitude modulation) constellations over additive white Gaussian noise (AWGN) and fading channels. We also show how these expressions can be extended to generalized hierarchical M-QAM constellations (square and rectangular). For the AWGN case, these expressions are in the form of a weighted sum of complementary error functions and are solely dependent on the constellation size M, the carrier-to-noise ratio, and a constellation parameter which controls the relative message importance. Because of their generic nature, these new expressions readily allow numerical evaluation for various cases of practical interest.

Hierarchical constellations offer a different degree of protection to the transmitted messages according to their relative importance. As such they found interesting application in digital video broadcasting systems as well as wireless multimedia services. Although a great deal of attention has been devoted in the literature to the study of the bit error rate (BER) performance of uniform phase shift keyed (PSK) constellations, very few results were published on the BER performance of hierarchical PSK constellations. We obtain exact and generic expressions in M for the BER of the generalized hierarchical M-PSK constellations over additive white Gaussian noise (AWGN) and fading channels. For the AWGN case, these expressions are in the form of a weighted sum of Pawula (1982) F-functions and are solely dependent on the constellation size M, the carrier-to-noise ratio, and a constellation parameter which controls the relative message importance. Because of their generic nature, these new expressions readily allow numerical evaluation for various cases of practical interest.

Hierarchical constellations offer a different degree of protection to the transmitted messages according to their relative importance. As such they find interesting application in digital video broadcasting systems as well as wireless multimedia services. Although a great deal of attention has been devoted in the recent literature to the study of the bit error rate (BER) performance of uniform quadrature amplitude modulation (QAM) constellations, very few results have been published on the BER performance of hierarchical QAM constellations. Indeed the only available expressions are "leading-term" approximate BER expressions for 4/16-QAM and 4/64-QAM. In this paper, we obtain exact and generic expressions in M for the BER of the 4/M-QAM (square and rectangular) constellations over additive white Gaussian noise (AWGN) and fading channels. For the AWGN case, these expressions are in the form of a weighted sum of complementary error functions and are solely dependent on the constellation size M, the carrier-to-noise ratio, and a constellation parameter which controls the relative message importance. Because of their generic nature, these new expressions readily allow numerical evaluation for various cases of practical interest. In particular, numerical results show that the leading-term approximation gives significantly optimistic BER values at low carrier-to-noise ratio (CNR) in particular over Rayleigh fading channels but is quite accurate in the high CNR region.

Based on a Karnaugh map style Gray coding of constellations, we derive a recursive algorithm for the exact bit error rate computation of generalized hierarchical M-ary pulse amplitude modulations (PAM) over additive white Gaussian noise (AWGN) and fading channels. We also show how this algorithm can be extended to generalized hierarchical quadrature amplitude modulation constellations (square and rectangular). For the AWGN case, these expressions are in the form of a weighted sum of complementary error functions and are solely dependent on the constellation size M, the carrier-to-noise ratio, and a constellation parameter which controls the relative message importance.