Regularized ZF in Cooperative Broadcast Channels under Distributed CSIT: A Large System Analysis

Obtaining accurate Channel State Information (CSI) at the transmitters (TX) is critical to many cooperation schemes such as Network MIMO, Interference Alignment etc. Practical CSI feedback and limited backhaul-based sharing inevitably creates degradations of CSI which are specific to each TX, giving rise to a distributed form of CSI. In the Distributed CSI (D-CSI) broadcast channel setting, the various TXs design elements of the precoder based on their individual estimates of the global multiuser channel matrix, which intuitively degrades performance when compared with the commonly used centralized CSI assumption. This paper tackles this challenging scenario and presents a first analysis of the rate performance for the distributed CSI multi-TX broadcast channel setting, in the large number of antenna regime. Using Random Matrix Theory (RMT) tools, we derive deterministic equivalents of the Signal to Interference plus Noise Ratio (SINR) for the popular regularized Zero-Forcing (ZF) precoder, allowing to unveil the price of distributedness for such cooperation methods.Comment: Extended version of an ISIT 2015 submission. Addition of the proofs omitted due to space constrain

Abruptio placentae with type II respiratory failure secondary to acute interstitial pneumonia responsive to steroids.

Acute Interstitial Pneumonia (AIP) is categorized as Idiopathic Interstitial Pneumonia (IIP), in which the cause is unknown. Ayoung female of 22 years presented in 34 weeks gestation with abruptio placentae (AP) and underwent Lower Segment Caesarian Section (LSCS) for AP. It progressed to type II respiratory failure secondary to AIPon 4th day post-surgery. It remained unresponsive when treated with noninvasive ventilation (NIV-BiPAP) along with antibiotics. Later, a trial treatment of pulse therapy of Methylprednisolone was executed on 7th day post-surgery which resulted in dramatic improvement in symptoms. It is uncommon to have type II respiratory failure secondary to AIP, and it is rarely steroid responsive

On the Capacity of the Two-user Gaussian Causal Cognitive Interference Channel

This paper considers the two-user Gaussian Causal Cognitive Interference Channel (GCCIC), which consists of two source-destination pairs that share the same channel and where one full-duplex cognitive source can causally learn the message of the primary source through a noisy link. The GCCIC is an interference channel with unilateral source cooperation that better models practical cognitive radio networks than the commonly used model which assumes that one source has perfect non-causal knowledge of the other source's message. First the sum-capacity of the symmetric GCCIC is determined to within a constant gap. Then, the insights gained from the derivation of the symmetric sum-capacity are extended to characterize the whole capacity region to within a constant gap for more general cases. In particular, the capacity is determined (a) to within 2 bits for the fully connected GCCIC when, roughly speaking, the interference is not weak at both receivers, (b) to within 2 bits for the Z-channel, i.e., when there is no interference from the primary user, and (c) to within 2 bits for the S-channel, i.e., when there is no interference from the secondary user. The parameter regimes where the GCCIC is equivalent, in terms of generalized degrees-of-freedom, to the noncooperative interference channel (i.e., unilateral causal cooperation is not useful), to the non-causal cognitive interference channel (i.e., causal cooperation attains the ultimate limit of cognitive radio technology), and to bilateral source cooperation are identified. These comparisons shed lights into the parameter regimes and network topologies that in practice might provide an unbounded throughput gain compared to currently available (non cognitive) technologies.Comment: Under second round review in IEEE Transactions in Information Theory - Submitted September 201

Unicameral bone cysts: Current concepts

Unicameral bone cysts (UBC) or simple/solitary bone cysts are benign fluid filled cavities that enlarge over time, resulting in thinning of the bone. Usually these cysts are reported in the metaphyseal areas of long bones with open physes. 85% of UBCs occur almost exclusively in children and adolescents. UBCs are more aggressive in the first decade of life and correspondingly the recurrence rate for these patients is four times that for adolescents. The proximal humerus and femur account for almost 90% of these cases. UBCs are classified as active when they are within 1 cm of the physis and latent as they progress to a diaphyseal location. Differential diagnoses for UBC include aneurysmal bone cyst, fibrous dysplasia, enchondroma, and intraosseous ganglia. By the time of skeletal maturity most UBCs tend to resolve. Nonoperative treatment may be a viable option for many patients with small or symptomatic lesions. Interventions include steroid injection, open curettage and bone grafting, decompression and percutaneous injection of marrow or graft substitutes

Non-traumatic coma in paediatric patients: Etiology and predictors of outcome

Objective: To determine the common etiological features of non-traumatic coma in children and evaluate possible predictors of morbidity and mortality in these patients.Method: A cross sectional study was carried out at the Paediatric Department of Civil Hospital Karachi from February 2008 to February 2009. In total 100 children, up to 14 years of age having history of non-traumatic coma were included. At the time of enrolment demographic data, clinical features, laboratory parameters and radiological workup were recorded. Data was entered and analyzed with SPSS version 16. Descriptive statistics were generated for all variables. Relationships between categorical variables were evaluated by examining cross-tabulations, chi2 test and Fisher\u27s exact tests. P-values \u3c 0.05 were considered statistically significant.Results: Mean age of the patients in months were 45 months. Male female ratio was 1.45:1. Among 65 survivors 38 (58%) showed no disability and 27 (41%) showed disability. Infections emerged as major cause of mortality (n=23, 79%). Clinical features that showed association with mortality included hypothermia (P = 0.032), hypotension (P = 0.002), altered breathing pattern (P = 0.0001), non reactive pupils (P = 0.001), low Glasgow coma scale (GCS) (P = 0.038), hypotonia (P = 0.002), hyporeflexia (P = 0.0001) and muscle power score of two (P = 0.043).Conclusion: Infections were the leading cause of non-traumatic coma as well as the leading cause of mortality in our study. Hypothermia, hypotension, altered breathing pattern, non reactive pupils, low GCS, hypotonia, hyporeflexia and low muscle power score were significantly associated with mortality in children presenting with non-traumatic coma

Energy efficiency benefits of RAN-as-a-service concept for a cloud-based 5G mobile network infrastructure

This paper focuses on energy efficiency aspects and related benefits of radio-access-network-as-a-service (RANaaS) implementation (using commodity hardware) as architectural evolution of LTE-advanced networks toward 5G infrastructure. RANaaS is a novel concept introduced recently, which enables the partial centralization of RAN functionalities depending on the actual needs as well as on network characteristics. In the view of future definition of 5G systems, this cloud-based design is an important solution in terms of efficient usage of network resources. The aim of this paper is to give a vision of the advantages of the RANaaS, to present its benefits in terms of energy efficiency and to propose a consistent system-level power model as a reference for assessing innovative functionalities toward 5G systems. The incremental benefits through the years are also discussed in perspective, by considering technological evolution of IT platforms and the increasing matching between their capabilities and the need for progressive virtualization of RAN functionalities. The description is complemented by an exemplary evaluation in terms of energy efficiency, analyzing the achievable gains associated with the RANaaS paradigm